There's a lot of things I strongly detest about a lot of user interfaces I see day to day. One thing is when stuff moves around due to loading, or events. Because inevitably they move when I am just about to try to tap/click on them, and then either nothing happens, or something entirely different happens.

(I think Google design seems to be especially rife with this kind of blatant asinine dumb stupid in your face badness, both on the web and on Android. But of course the web mostly sucks that way too - people don't even seem to be able to set the width and height properties on their images so when the load the whole page shuffles around.)