Just about any moron (mostly on YouTube, the grande cesspool of idiots, but elsewhere) that undertakes pretty much any of the following beliefs pisses me off:
Any cartoon
not from the 1940's or 1990's sucks
All anime or manga sucks
Anyone who likes aforementioned anime sucks
Anything non United Statesian in origin sucks
Military brat people
Rich 14 year olds who blow their money on stupid crap, gloat about it, and rub it in my face
Anyone who says people who don't play runscape or WoW
don't have a life (YES, these people exist)
Anyone who keeps telling me to get a life, and they don't have one of their own
Anyone who tries to act clever, and make you look like a fool, when they don't know jack dirt
Anyone who lies, and won't admit it, or can't hack up proof on what they're on about
Internet hotshots (nuff said)
And anyone who takes everything, as in everything, seriously.
Hmm, reasons should be obvious, can't say much more. Sorry. :\