PET PEEVES!!!!
Just list random you care that people must do a certain way.
It really grinds my gears when someone forgets to change there status on skype to Online, - I mean you took the time to log back on and yet you wont change the little icon, its so user friendly.
It really grinds my gears when someone forgets to close there BBCode on a Forum and it messes with there whole topic. - I mean you obviously were typing out your whole BBCode instead of using the forummotion handy bar so do it right, or dont bothing using it.