In my jr. high days, I worked as a PC repair technician for a very small computer store. I'd add / replace hardware, then install the drivers for DOS, then get whatever apps they had installed to work with, say, the new bus mouse.

Sometimes (often) a person would ask what I'd done to "make it work". I could explain all day, but I'd end up trying to train someone to do my job who wasn't really interested in it, and instead wanted the one paragraph answer so they could sound like geeks to their friends (why? your guess is as good as mine.) However, normally after a few key words, the inquiring person's eyes would glaze over, and you could just tell that they wanted you to wrap it up before they looked dumb -- they had ceased being able to follow the answer, were no longer interested, and wanted to go.

It was even worse when you just started in before they asked. The eye glaze happened immediately. Even if they were trying to follow you so that they could interject a question or comment, they couldn't. They were done, and you were talking to someone who was in "config.sys mode". We called it that because mentioning config.sys was a sure-fire way to get the glaze. People didn't understand why putting a line in that one file made thier mouse work. You say "I added the drivers to your config.sys, then reordered the loads for optimal memory usage...", and boom... gone.

I'm remembering this today because I've seen it twice now in 24 hours.. The only problem is, I'm now noticing it when I do it. The first was me trying to explain the ASP.NET pipline, and the concept difference between ASP's global.asa, and ASP.NET's global.asax, and what a handler vs. module is, blah, blah, blah.... to a project manager. I thought I was being clear and interesting, and that the subject was fascinating. I was wrong. He went into config.sys mode.

More scary was yesterday - My neighbor is explaining to me why my mower isn't working well, and started in on some explanation of the exhaust backpressure in a 2-cycle engine.... or something. After about five minutes of not at all understanding what he talking about and feeling like a two year old trying to understand how black holes can emit radiation from the event horizon, I realized it. I was now in config.sys mode. I was the guy who we snickered about after he left the PC shop. I was the clueless marvel calling a 3.5" floppy a "hard disk". (even worse, when my neighbor said "you look lost", I actually said "config.sys mode. Sorry." Could I be more of a dork? Perhaps I should wear the propeller beanie next time)

So please - the next time you're explaining something to someone that doesn't get it, and you just know that they should understand you.. Don't assume they're an idiot (even if they are).

It probably happens to you, more often than you think.