What's your pet peeve?

I think loud chewing is probably one of my pet peeves too, it drives me absolutely crazy! i can't eat in a room with my father because he chews so loudly and makes such a lot of noise when he eats it puts me off my food, he really doens't realise he is doing it though! it drives me absolutely crazy! another one of my peeves is when people always think they know everything, even when they clearly don't, if they don't know about something they should just say so or ask about it rather than pretending they know what they are on about and talk nonsense!! hehe xxx