In no particular order (just few random things I cannot stand):
Racists
Bigots
Machism
Spiders (yes, remember the "Phobias" thread?)
John Lennon
Summertime
TV Stars
Ignorance
Motorcycles
Bellyaches
Brainless Patriotism
Disrespectful people
Hamtaro Hamster
Global Americanisation
Self-proclaimed geniuses
Many of these things don't need an explanation. Regarding the others: motorcycles because I have a group of motorcycles fanatics racing outside my window who are not allowing me to sleep at night (if only I could use a lightsaber to make them stop!); Hamtaro Hamster because that stupid little animated character is just nauseating and it just make me want to kill it ( only in this case I'm not against cruelty towards animals
) ; summertime because hot weather makes me feel all dizzy and weak, plus I don't like being tanned and sweating all time; John Lennon because I can't see how people can love his songs, filled with stereotypes and fake ideals (he doesn't sound genuine at all to me, but he pretended to be), plus I guess anybody must feel a instictive hostility towards some famous pop icon
That's all I can think of at the moment.