Virtual PC and the lack of Maximize button
Nowadays, it's unbelievable that an application has the Maximize button disabled. Even more if it's an application I use everyday and which most of the time NEEDS to be maximized.
Resizing the stupid window so that it fits the entire desktop area of my laptop, and at the same time trying the resolution in the guest OS to fit instead of show scrollbars is one of the most annoying experiences I have with Virtual PC every damn day...