Do you have any real actor or game/movie character that annoys the hell out of you?
I enjoy 2 Broke Girls quite a lot but that thing called Sophie? Sweet Jesus, I wish there was a 'skip scene' button just for her "acting".
In games, GTA IV's Roman Bellic takes annoying to a whole new level, I think he is the main villain after all.
The voice acting in Two Worlds made me quit. I think it's the only game I quit specifically for bad acting. The (English) voice acting in Dark Souls 1 didn't make me quit, I quit playing for other reasons though, but also contributed to my "wtf is this [censored]" stance. When you have so little dialogue, make it at least decent, lol.