My biggest frustration has been the lack of feedback from users. As all developers know, there is little difference between an application doing what the user wants and an application not being used. Neither case generates bugs and feature requests. Perhaps there’s more evidence-of-use with web apps, but I’ve not lived there.

I prefer to think they’re just good applications that stand the test of time, but…. Indirect evidence is all I have, from the literature, conferences or the occasional comment from support or sales.