I have a few and will add more later as I think of them.
1.People with voice activated mics with a nasal whissle and or a loud keyboard.
(this next one is kinda strange)
2.I hate it when I am at the house D vendor and somone runs infront of me and stands on the counter top. Or I come into the store and the vendor is practically impossible to find due to people on the counter top blocking him from view.
I know the second one is a little goofy but for some reason it gets me all in a twist. I even go so far as to RP a little in stores insulting people on their up-bringing for not being taught it was improper to stand on a merchants counter top.
Add your own in here if you have em. If not then :P