Basically, because they're a poor cover-up for crap design.
I mean, Flash is cool. Flash is great, but I'm sick of seeing sites where someone thought they could get away with not bothering about functionality, usability or esthetics just by using flash.
So, for the benefit of those garage designers who can't afford to run a user survey, here's a few things I'd like to be able to do on your site:
- Copy your phone number into my contact management software.
- Bookmark or link to a specific bit of information I liked.
- Set my own font size (yes, I'm sure it looks great on 860x640. Get a life).
- See the name of the page I'm looking at in my title bar.
- Send you a link to a page with a typo and see you fix it in 5 minutes, without it costing a small nations GDP.
- Zoom in on a picture.