Roland Weigelt

In a past blog post I wrote about a surprising change I encountered during the migration of a .NET Core 2.2 application to .NET Core 3.0. I have just migrated that same application to .NET 5 and guess what, I stumbled across another “tiny difference with big consequences”.

The situation: I have a WPF desktop client that communicates with an ASP.NET Core server that in turn communicates with a small TypeScript browser application. I use Web API for accessing files and meta data, and SignalR to call remote functions.

After the migration I ran the application and things were working fine – until a certain point, where I received the following exception in a call of SignalR’s HubConnection.InvokeCoreAsync() (actual function name replaced with “doSomething”):

Microsoft.AspNetCore.SignalR.HubException
   HResult=0x80131500
   Message=Failed to invoke 'doSomething' due to an error on the server.
   Source=System.Private.CoreLib

On the server side, my own code was not even called.

It took me a while to notice that one of the parameters of the function had the type of a class with a specific constellation of constructors:

• A public constructor with parameters
• A private default constructor.

It turned out while SignalR in .NET Core 3.1 has no problem (de)serializing an instance of a class with a private default constructor, SignalR in .NET 5 does. So simply removing that constructor fixed the problem. In terms forcing the usage of the other constructor when explicitly creating objects of that type, nothing changed; I did not need a private default constructor for that.

P.S. Do not ask me why I had a private default constructor in the first place. But the project is a couple of years old now, and things like this do happen.

Today I played around with some code in an WPF application that opens a (COM-style) properties dialog.

When opened outside my application, the dialog looked like this:

But when I opened the dialog from my code, it looked like this:

The solution is simple but appears blog-worthy to me because I had a hard time searching the Web using rather unspecific search terms like “properties dialog”, theme, style, etc.

In the end I came across a theme-related Microsoft article for C++ mentioning a manifest file and connected the dots to a StackOverflow question/answer about changing the Windows User Account Control level for a C#/WPF application using a custom manifest.

What to do

Create the custom manifest file

• In Visual Studio (2019), open the context menu of the project for the WPF application.
• Add > New item.
• Ctrl+E (to jump to the search box), enter “manifest”.
• Press the “Add” button to add the “app.manifest” file to the project.
• Visual Studio selects the file automatically (see project properties > Application > Resources > Icon and manifest > Manifest)

Edit the manifest

• Open the “app.manifest” file.
• Scroll to the bottom.
• Uncomment the section behind the “Enable themes for Windows common controls and dialogs (Windows XP and later)” comment.
• Rebuild.

That’s it!

In case you are wondering about my (webcam) experiment: This will be the topic of an upcoming blog post.

In a previous blog post I wrote about how mental models help you understand how something works. These models in your mind explain what did happen in the past and provide a reasonable (but not always reliable) prediction for will happen in the future. Interestingly, mental models can do that even though they are simplified, incomplete, and often enough simply wrong.

Empathy also has been a topic on my blog; I wrote about what it is and why it is important and why it is good for you, too.

In this article, I combine the two topics and present you my personal mental model of empathy. Note that it is a mental model, not the mental model for empathy. As such, it is, well… simplified, incomplete, and probably wrong. Still, it is “good enough” for many purposes and hey, it comes with pictures!

To start things off, imagine you have developed a non-trivial application as a single developer.

You, the developer

Here you are, living in your frame of reference, depicted as a nondescript coordinate system:

(I learned at university that axes without units are the worst. Have I told you how mental models are likely to be incomplete?)

Your knowledge about the application

This is what you, the developer, could theoretically know about the application:

You, the user

Now you try to imagine “the user”. Not being the developer of the application, the user is in a different situation:

A first step is trying to put yourself in the other person’s shoes:

The user’s knowledge about the application

You assume that not being the developer means that you cannot have knowledge of the inner workings. As a user, you only have the UI, the manual and other public sources at your disposal for understanding the application. This means that the user inevitably must know less about the software:

Next you are trying to employ some empathy. You think that it is unrealistic that user has read and understood all publicly available information. So most likely the user will know less than theoretically possible:

(Let’s ignore the relative sizes, you get the idea)

But: You are not the user

Always be aware that it is not you, but somebody else in the situation you are looking at:

This person could be highly motivated to use your application. Never underestimate the amount of work people will put into learning something if they feel it enables them to create results that are worth it. Just think how deep some people dig into Adobe After Effects or Microsoft Excel.

But in general, users most likely acquire just enough knowledge to get the job done. This means that they will know next to nothing about some features. At the same time, they can be very proficient in other features if a task at hand demands it.

So the graph depicting the user’s knowledge could look like this, with the sectors standing for parts of the application or large features:

Another user

A different person…

…may use the application for other purposes.

He or she may have more or less experience, in different areas:

A good start, but not quite there, yet

At this point, we have established that you are not the user and that different users have different needs and thus varying levels of knowledge.

But we are still stuck in our own point of view. For instance, we assess the user’s knowledge in terms of the application’s structure as we see it from a developer’s perspective. Even if we consider scenarios during development, we still tend to think in application parts as well as larger or smaller features.

Next: Stop thinking in your frame of reference

The next step is to acknowledge that users have a different frame of reference. As developers, we work on our software for long periods of time, which gives it a high importance in our daily life.

For users, our software is just another application. For them, is is not exactly the center of the universe.

Or, in other words, they live in their own coordinate system:

As an experiment, try to watch yourself how you use and experience the software you did not develop yourself. How different applications, tools and utilities have different importance. And how some software simply does not excite you enough to really learn more than the absolute basics about it.

Now capture that feeling. Be assured, some user out there will feel the same towards your application. A user like this may never become a big fan of your software, but if you design for them, you automatically help everybody else.

If you…

• lead the eye to the right points (by visual design, not a way-too-long onboarding experience)
• write clear UI texts (that even people can understand who do not want to read) and
• design features that are not simply thin UI layers over existing APIs (because users do not think in APIs),

everybody wins.

Using the software vs. getting the job done

Some application features map directly to a user scenario, some scenarios may span multiple features.

But be aware that “real world” scenarios do not necessarily start and finish inside your software. Users may start with ideas, thoughts, purpose, constraints, raw data, etc. outside your application. The work done inside the application may be a first step towards something very different (which means that e.g. a simple CSV export feature can be more important than the fancy result display that you developed). And in between, the scenario may take the users to use other software.

A person in the situation of achieving a specific goal will likely have a different view of the world. To visualize this, think of a coordinate system that looks very different from yours:

Things to remember

• The way you view your application is influenced by your knowledge of application parts and individual features.
  Other people may view it in a different way, based on what they see along their path through the user interface.
• Assume that people do not actually want to use your software, they want to achieve a specific goal.
  If that aligns with your software, good for everybody.
• Be aware that even though you and your users have the software as a connection point, your world view may be very different
  As a visual reminder, imagine yourself in a cartesian coordinate system and the user in a spherical coordinate system with a different origin. Neither of you lives in the “correct” or “better” coordinate system, they are just different. But the other coordinate system surely does not have your software as the center of the world, that is for sure…

P.S.

If you are interested in a (non-technical) example of completely different coordinate systems, take a look at my post “Exercise in Thinking: Do Racing Stripes Make a Car Go Faster?”.

In my spare time, I work on a software for the courtside advertising system of a local sports arena. To create the playlists for the advertising loops on the LED modules, users can drag and drop preview thumbnails of video and image files. Which brings us to the topic of this blog post, i.e. how to create these thumbnails.

Ways to create thumbnails

Win API

When I started the project in C#/WPF many years ago, I used some Win API code from a StackOverflow answer by Daniel Peñalba.

StorageFile.GetThumbnailAsync

After a failed attempt at a UWP rewrite, my software now runs on .NET Core 3.1, with a WPF management client, a ASP.NET/SignalR server and a HTML5/Typescript playback client (using a Chrome browser in kiosk mode, although I may change that when Microsoft Edge WebView2 comes out of preview).

Working with UWP introduced me to StorageFile.GetThumbnailAsync, which I kept using because the StorageFile API also gives me easy access to metadata (e.g. width, height and duration of a video).

The StorageFile API is not exactly known for high performance, but in my case this is not an issue, because the number of media files added in one go is typically in single digits.

FFmpeg

As mentioned above, StorageFile.GetThumbnailAsync works for me. So, why am I considering another method for the next version of my software?

For an answer I have to digress a bit: My software initially used individual MediaElement controls for the eleven LED modules. While I did manage to sync up the video playback, making it robust and reliable for many hours of looped playback required many workarounds in the code. To make matters worse, the reliability depended on the video format.

The videos to be played come from a variety of sources; some are produced by advertising agencies or video production companies, others are the work of semi-professionals. Some match the requested specs, many do not. In the end, I made it a habit to transcode each video myself.

Fortunately, this did not cause a noticeable loss of quality. Which encouraged me to try a different approach when I rewrote the playback to be performed in a browser. Now my software uses FFmpeg to combine the individual videos into one MP4 file. FFmpeg is “A complete, cross-platform solution to record, convert and stream audio and video” and this quote from the website is not an understatement.

In addition to offering a wide variety of features to manipulate inputs and outputs, FFmpeg also has been able to handle virtually any media file it has come across so far. Until now I could not fully benefit from this robustness because StorageFile.GetThumbnailAsync does not work with the same range of file formats. For example, on my computer, MOV files cause an exception (note the emphasis, YMMV).

FFmpeg to the rescue: Creating a thumbnail from a video or image file is something that FFmpeg can do easily – with two caveats:

1. It is slower than GetThumbnailAsync (at least when calling the executable as a separate process, like I do)
2. It does not work for general purpose files, only for videos or images.

My plan is to continue to use StorageFile.GetThumbnailAsync as the default method and to use FFmpeg as a fallback in case of an exception.

Demo code

I have posted a Visual Studio demo project on https://github.com/RWeigelt/ThumbnailCreationDemo. The code shows the use of StorageFile.GetThumbnailAsync and FFmpeg (for Win API, see the StackOverflow answer). Please note that the code is not intended to be a ready-to-use library; instead, you should run the demo, maybe set a few breakpoints, follow the code and use the parts that are of interest to you.

A few prerequisites:

• Your Visual Studio 2019 (I used 16.7.1) should be able to compile .NET Core 3.1 command line applications.
• You must have FFmpeg on your computer. You can get it from https://ffmpeg.org.

• Before you run the project, change the following line in “Program.cs” so the path matches the location of the FFmpeg executable on your computer:

  const string _FfmpegExeFilePath = @"C:\Program Files\FFmpeg\bin\ffmpeg.exe";

The project comes with two example files, “Image.png” and “Video.wmv”, with 768 x 80 pixels each (the size of a LED advertising module). During a build, the files will be copied to the output directory.

Running the project inside Visual Studio creates two thumbnail files for each media file (“…thumb1.png” and “…thumb2.png”). At the end you will be offered to open an Explorer window for the output directory, so you do not need dig around in the file system.

While the code for using StorageFile.GetThumbnailAsync is straightforward, the usage of FFmpeg needs some explanation.

The call of ffmpeg.exe is hidden behind a Task using a TaskCompletionSource. For the purpose of the demo code, the Task returns the duration in milliseconds (instead of e.g. the exit code of the FFmpeg process). This is something you may want to change for production code.

The command line parameters:

• For video files,
• -ss 5 means “seek to the position five seconds into the media file”.
• -an prevents audio streams from being handled in any way
  
• -i specifies the input file
• -vframes 1 gets one frame from the input file
• -s specifies the output size
• -y to confirm overwriting an existing file
  
• The last parameter is the output file; the extension of the thumbnail file tells FFmpeg that we want the file in PNG format.
  

Note that the order of the parameters makes a difference: Parameters in front of the input file (-i) are treated as options that affect the input, parameter behind affect the output.

For instance, the -ss 5 in front of the -i simply seeks into the file (as one would expect). If the -ss 5 is placed behind the -i, then FFmpeg will actually decode five seconds of the input file frame by frame, which takes more time. The difference is noticeable even for this simple demo, try it out. For more information see https://trac.ffmpeg.org/wiki/Seeking.

What about metadata?

As I wrote, on my computer, calling StorageFile.GetThumbnailAsync causes an exception for a MOV file (yes, this could surely be fixed with the right codec pack, but for the moment I keep things the way they are to test error handling).

But I can retrieve metadata using StorageFile.Properties – that is because the metadata is not determined at the moment I ask for it, it simply is read from the file without actually looking at its content. This is fortunate because for my purposes, reading the metadata via the StorageFile API is much easier than using e.g. ffprobe’s output.

My day job sometimes involves reviewing existing or planned user interfaces of business applications outside my product team. When I give my feedback to frontend developers, I try to use the opportunity to convey knowledge on UI/UX basics. For instance, by showing them how my findings are informed by a set of questions that can they can use themselves as an early check of their work.

One of these questions is: What is the intended mental model?

I find it helpful because in my experience,

• it highlights problems in a constructive way and
• is a great starter for discussions on working towards a solution.

So, let’s talk about mental models.

What is a mental model?

Generally, a mental model is a simplified, often incomplete (or even wrong) representation of the surrounding world in your mind. The model forms based on the available visible, audible, or sensory information, prior personal experience, what other people have told you or just by guessing.

The benchmark for a mental model is how good it helps you navigate the real world, i.e. if it can explain something that has happened or can offer a reasonable prediction for what will happen.

Take gravity for example. The simple mental model of “things falls down until they get stopped by something” is good enough for most situations in our everyday life.

If a mental model fails to explain an observation (“why doesn’t this ‘balloon’ thing fall down?”) or when additional information becomes available (Helium is lighter than air), the model may evolve, be replaced by another model, or by several models for different situations. But the model(s) remain simple – you usually do not explicitly think about buoyancy if no water is involved, or the gravitational forces that cosmic objects exert on your car.

Example: A mental model for scrolling

Let’s get back to user interfaces. Imagine you have never seen something like scrolling before. Then you watch somebody drag the narrow rectangle at the right side of the window down, causing the larger part to move up:

After you have seen some more scrolling, noticing that content that left the screen can be brought back, the mental model in your head will most likely look like this:

Is this model correct? Do the areas in light gray really exist?

From a purely technical point of view, this is debatable – especially when you think about virtualized scrolling, where the UI “lies” to you, creating the visible part on the fly from pure data (e.g. the text in a text editor).

From a user’s point of view this is not important. The model explains why parts of the screen moved the way they did when you moved the scrollbar. And it allows a reliable prediction what action will bring back content that was moved off the viewport.

In other words: The model is good enough.

Visual cues are key

When a user perceives an application as easy to understand, it means that he/she was able to quickly develop an initial mental model that matches the reality of the user interface. That model surely will continue to grow and evolve and may have to be adjusted over time. But what to look out for are gross misunderstandings, when a wrong mental model leads to confusion, or worse, data loss.

Your job when designing a UI is to “nudge” the user towards a correct mental model. This is a case of “show, don’t tell”: Explaining the basic ideas of the UI in an online manual or a onboarding experience (likely to be skipped) will not reach all users. The UI needs visual cues that convey the mental model that you intended.

For example, when you cannot show all content at once due to space constraints, you somehow must tell the user that there is more content to discover:

• Partially visible content that gets cut off at an edge hints that the area can be scrolled or at least resized.
• Page numbers or simply dots look like paging is possible.
• Stack-like visuals suggest that content can be switched.

Example: A mental model for tabbing

Tab views show different sets of one or more controls in the same space. This user interface pattern is useful if you…

• cannot (or do not want to) show all controls at the same time, but need fast switching and
• you can cluster the controls into groups that make sense.

A mental model for a tab view comes straight from the real world, just imagine e.g. three sheets of paper:

Like other UI elements, the design of tabs has evolved over the years. Moving away from mimicking physical objects and their behavior, the overall trend went to visually reduced designs.

While the following design still tries to convey a foreground-background relationship…

…the second version does not care about how things would work in the real world:

Which is not necessarily a bad thing, to be clear. In UI design, you must deal with the fact that a user has a certain “attention budget”. In your UI, each pixel different from the main background color chips away from that budget. Thus, getting rid of lines, borders and colored area is a good way to reduce “cognitive load” – until it is not. This is the point when you have removed important visual cues that help forming the mental model that you originally intended.

How visual cues influence your mental model

Look at the following four sketches of an application with two levels of navigation:

Notice how the gray backgrounds influence your mental model:

• The upper left does not give you an idea what to expect when you click an item in the top row or one of the icons on the left side.
• The lower right is very clear about the relationships of the different parts of the UI. At the same time, the design is pretty “busy”.
• The upper right and lower left are similar in design but convey different mental models. Which one is “better” depends on factors like scrolling, expected window sizes, etc. So, the answer is the usual “it depends”.

Ask yourself: What is the intended mental model?

The application

Users do not develop a mental model in a vacuum. They look for similarities to other applications. In unfamiliar situations, their behavior is influenced by earlier experiences. While not all applications are the same, certain archetypes have developed over time.

If you aim for a quick route of your users to familiarity with the application, you should be clear about the general model. For instance:

• Is the application a document editor?
  Most business users know how to to deal with Office documents. If your application has “things” that can be handled like documents (regardless of whether they are actually stored in files), users can use their previous experience with documents. At the same time, this comes with certain expectations. For example, editing or deleting one “document” should not affect another document (unless there is an explicit relationship).
• Is it something that manages one or more lists of “things”, offering views on the data at different detail levels?
  This is the model behind applications that have some kind of database at their core. Browsing, searching, or filtering, followed by viewing/editing of single data items are comparable across business applications. Users of your application could e.g. expect that after they have narrowed down the results list, and dive into a single item, that the list will be “somewhere off-screen”. This is an example where a mental model is used for predicting what will happen, i.e. that is possible somehow to come back to the result list.
• Is it like a machine that builds something after you have specified what you want to build?
  Software that uses the concept of “projects” and “builds” is what developers work with all day. Some single-source documentation systems use the same approach. Another example are e.g. video production tools.

Your application surely can combine different models or be something unique. And if it is similar to existing software, being different can be an advantage. The best thing users can say is “it is like X, but you no longer have to do Y manually”.

What you must avoid is intentionally trying to be similar to other software and then offering a bad experience. For example, early web applications sometimes tried very hard to be like their desktop counterparts before the technology was reliable enough. Which could result in losing work simply by pressing a single key at the wrong time (some may remember: a page-based application, a large text field, some JavaScript that goes wild, lost focus, backspace – everything gone).

The data

Internally, most (.NET) applications deal with objects with properties which in turn can be objects, lists of objects or references to one or more objects. One of the challenges of UI design is to decide how much users should or should not know of these structures.

• Is what a user experiences as a “thing” the same as an object in your code?
  Sometimes it is good to hide the complexity of composite objects, sometimes it is not. Take, for example, a form for entering a person’s data. Do you present the address as something that feels like a “thing”, or as something that is part of the person similar to its given and family name? As usual, it depends. On one hand you want a clean and simple UI, on the other hand imagine a database that tracks all addresses that a person has ever lived at.
• How do you handle incomplete or invalid “things”?
  Let’s say a user has a concept of “things” that map pretty well to objects behind the scenes. Unfortunately, the infrastructure for storing these objects requires them to be complete and valid. Does this impact the user, forcing an “all or nothing” approach when creating a new thing? Or do you allow incomplete data as a “draft”, even if it means it must be stored separately because you e.g. have no influence on the available storage infrastructure?

What to do

• Prepare yourself to be asked “what’s the mental model?”
  Even if you will never get asked, this forces you to come up with a short summary that helps you communicating the basic ideas of your application (or a specific part of it).
• Remember mental models are simplified and incomplete
  When a user writes an email and presses the “send” button, in their mind, this sends the email. Conceptually, emails are moved into the outbox, then collected and sent. But even people who know about this (and may have seen an email stuck in the outbox) tend to think of “click equals send”, because this mental model is – you may have guessed it by now – “good enough”. When you think about mental models in your application, expect users to start with the simplest model they can work with.
• Watch yourself how you figure out how other software works
  Which visual cues do help you? Where does the software rely on known interaction patterns? Why can you use an application that you have not used before?
• Think of instances when your mental model was wrong
  Was it your mistake? Did you have assumptions based on prior experience? Was it the application’s fault? What could the software have done differently to prevent this? What about your application? Could this happen to users of your software?

This is a side-product of sketches I did for upcoming talks, using an iOS app called Linea Sketch.

User Interface

The user sees a button.

User Experience

How the user feels before, while and after pressing the button.

Feature

What the product does for the user when he/she presses the button.

Scenario

Who encounters what problem and how the product will help him/her on the way to reach their goal.

Oh, the button? You don’t think about the button when first looking at the scenario…that’s the point!

Eigentlich sollte die Developer Week 2020 vom 29. Juni bis 3. Juli 2020 in Nürnberg stattfinden. Ich wäre dort mit meinem Ganztages-Workshop “Von Null auf GUI – Design/UI/UX-Praxiswissen für Entwickler” und einem Vortrag über “User Interface Patterns” vor Ort gewesen – doch dann kam der Virus.

Daraus folgte zum einen eine Verschiebung in den November, und zwar als Hybrid-Modell (sowohl On-Site als auch Remote). Mein Workshop ist jetzt für den 2. November, der Vortrag für den 4. November geplant.

Darüber hinaus wird im ursprünglichen Zeitraum eine reine Online-Konferenz, die DWX Home, stattfinden. Jeweils vormittags gibt es Vorträge zu den Themen DevOps (Montag, 29. Juni 2020), .NET (Dienstag), Testen (Mittwoch), Software-Architektur und -Qualität (Donnerstag) sowie UX und UI Design (Freitag, 3. Juli 2020).

Am UX und UI Design-Tag bin ich mit meinem Vortrag “Fragen, Fragen Fragen…- Diskussionen über UI-Designs” vertreten:

Die richtige Frage zum richtigen Zeitpunkt kann Diskussionen über UI-Designs wertvolle Impulse geben. Dabei muss weder die Frage noch die Antwort besonders weltbewegend sein – ein kleines Stückchen vorher unbekannter Information verändert manchmal massiv den Lauf der Dinge.

In seinem Vortrag vermittelt Roland Weigelt, dass eine analytische Denkweise auch in den vermeintlich eher von Emotionen bestimmten Bereichen Design und User Experience ein wertvolles Werkzeug ist. Und damit es nicht zu trocken wird, geht es nebenbei um Problemlösung à la Indiana Jones, außerirdische Lebensformen und den Einfluss von Rallye-Streifen auf die Geschwindigkeit von Sportwagen.

Für Teilnehmer der Developer Week im November ist der Zugang zur DWX Home automatisch im Ticket-Preise inbegriffen. Für alle anderen gibt es kostengünstige Tagestickets (dafür auf der Ticket-Seite ganz nach unten scrollen).

The progress from a junior to a senior software developer shows in various ways:

• Coding: Years of working with different languages, frameworks, libraries and architectures help developing a gut feeling for technology.
• Planning: Having experienced a large number of projects or product releases with their milestones, last-minute changes, hotfixes, updates, etc., senior developers usually have a better sense of what to do and what to avoid.
• Analytical thinking: (Good) senior developers tend to ask the right question at the right time, digging deep to find out what they don’t know – and whether what they think they know is true.

For developers, improving their analytical skills is an important part of personal growth. That is why I like to cover non-technical topics both in my conference talks as well in my blog articles.

In a previous post called “How to Approach Problems in Development (and Pretty Much Everywhere Else)”, I wrote about (among other things) what Indiana Jones can teach you about problem solving.

The article you are reading now asks whether “racing stripes” make a car go faster. A strange question on a software development blog. This is by design, because strange things tend to be remembered more easily (fun fact: The word “strange” can be translated to German as “merkwürdig”, which in a literal translation back to English could be “worthy to be noticed” or “worthy to be remembered”).

So: Do Racing Stripes Make a Car Go Faster?

When being pressed for a quick answer, most of us would likely go for a “No”.

On second thought, various considerations come into mind:

• Is the racing stripe applied in addition to the existing paint job?
• What about the weight of the paint for the racing stripe?
• What if the stripe is not done in paint, but with adhesive film?
• Or what if the whole paint job is replaced with a design including a racing stripe – and lighter paint is used?
• How much does the weight of the paint influence the car’s performance, anyway?
• …

Many well-intentioned questions, unfortunately focusing too much on details. On the other hand, one important question is missing: What kind of “car” are we talking about here, exactly?

What if the question is actually about toy cars?

• The car in question is now significantly smaller, while the size of the air molecules stays the same. Does aerodynamics play an important role here?
• Does the car have an engine? If not, is the car intended to roll down a hill? Maybe then more weight could be beneficial?

But: Are we not missing something here? If “car” was not what we expected, are our assumptions about “faster” still valid?

• What do we know about the context of the question?
• How exactly is “faster” determined?

Now imagine the following situation: You give two identical toy cars to a young child with an interest in cars. One car has a racing stripe (or a cool design in general), the other does not.

Now you ask the child “which car is faster?”, and if the child answers “the one with the stripes”, then this is the correct answer (for this child).

From our grown-up point of view, the faster car is the one that travels more units of distance per unit time. From the child’s point of view, the car that wins the race in their mind (“wroom, wroom!”) is the faster one. The laws of physics do not necessarily apply here.

Lessons learned

Be careful with your assumptions

Your personal experiences are an important foundation, but they can also mislead you. Be careful when assuming facts that were not explicitly mentioned. You may be subject to a misunderstanding. And even if not, “obvious” questions can still yield helpful information. If you have the chance to ask, use the opportunity. You never know when a question like “just to be sure, we are talking about X that does Y?” is answered “yes, exactly… well, ok, Z should be mentioned, too” – with Z being a vital detail.

Make sure terms are clearly defined

When you talk about X, make sure that you and everybody else agrees on what X is exactly. Take the term “combo box”, for example. Even though the word “combo” clearly hints at a combination (of a dropdown list and a text field), some people use the term “combo box” also for simple dropdown boxes.

From a technical point of view, this may be only “half wrong”, because in certain UI technologies, a combo box control can be turned into a dropdown list as an option.

But when speaking to colleagues or customers, this may lead to unnecessary confusion or even wrong expectations.

Be sure to know the context

A car on the street is different from a toy car in the hands of a young child.

A software that is a pleasure to use on your laptop while sitting on the couch can be a pain to use on a smartphone while trying to catch a train.

And for transferring huge amounts of data from location A to location B, a truck full of hard drives can be both a viable solution as well as a terrible idea.

Context matters. A lot.

Fully respect the target audience and their view of the world

This is where empathy comes into play, “the capacity to understand what another person is experiencing from within the other person's frame of reference, i.e., the capacity to place oneself in another's shoes” (quote).

For technical-minded people, empathy may sound like a touchy-feely topic, “about being nice to people”. For me, empathy in software development is about respect towards users and about being a professional.

If you are interested, I have published two articles about empathy with a focus on software development here on this blog (“The Importance of Empathy” and “It’s Good for You, Too!”).