One of the biggest things that bug me is bad text buttons. I hate haveing to click directly on the word.
Notice that good flash artist don't do that, namely Homestarruner.
I can always tell if a game is going to be crap or not, just by clicking on their play button.
 "Micro Olympics"){kind=icon}
 "=D"){kind=icon}
 "Deep In A Duengon"){kind=icon}
 "Lootcamp 2"){kind=icon}