I lose my temper when someone is messing with me and they start touching me. It won't affect me at all until they feel the need to touch/hit/kick me. Then I get a little ticked, I can usually keep my cool though anyway.
I get angry at people who don't rtfm, people who dislike a certain ethnicity or sexuality but can only support their opinion with stereotypes, people who throw around the word 'Communism' without knowing what it really means, people misusing the word 'Fascist' or 'Fascism,' teachers with no respect for their students, people who blast you with fundamentalist rhetoric during casual conversation, hypocrisy and hypocrites, the Yeah Yeah Yeahs, soda that's too sweet, people who don't spell words with vowels, karaoke, movie and videogame credits, MS Paint, Photoshop, GIMP, Adobe Illustrator, the Mac OS, Windows, obnoxiously bright lamps, things that stub my toe, idiots, mimickers, mockers, haters, naggers, picture frames, bland hot sauce, tissues that are too soft, the letter 'J,' people who try to speak 1337 but can't, people with bad spelling, people with bad grammar, people who don't think spelling or grammar are important, people who post in all caps, ans people who think that too many things make me lose my temper.
I get mad when someone acts stupid to impress someone. Also I hate when people think that death metal or any metal is better than all other types of music. That last one is kinda complicated.
I get very angry when someone hit's me on the back of the head. I mean I don't know why, when I get slaped, punched in the head I don't go over the top.
But when it's the back of the head, I get real angry.