People who shout at the tv. Rugby, movies, news, whatever. God I hate when people do that.
I am guilty of this. Especially during horror movies, I always feel the need to loudly tell the characters how stupid they are. Sometimes I even yell at the newspaper.
One of my biggest peeves at the moment is when people won't allow you to have an opinion because only theirs is the acceptable one. I've been noticing it a lot with one of my friends lately, he complains to no end about the music I listen to, but if I as much as go 'ugh' when he plays a song I don't like, he has a fit and starts saying things like "how dare you" and "it's brilliant music." When I try and explain to him that I feel the same about my music, he refuses completely to allow this and just stonewalls me telling me "no, it svcks." It's the only thing that really irritates me about him and when I try and explain it calmly he refuses to acknowledge my points.
(music is a very, very big deal to the both of us so it's never just a minor squabble, it becomes a full on screaming match XD)
Also, eating noises. I can't stand them. I know it's hard to eat silently, but people who slobber away with their mouths open making loud breathing noises at the same time drive me crazy. I always have to tell my mother to eat with her mouth closed.
Slow drivers. I don't care if they don't have to be anywhere on time, I'm late so pull the [censored] over and let me pass, then you can dawdle on your merry way.