Online ranked matches in ANY game, why even put in ranked? probably just to draw the bad players to it and leave all the good ones in player matches.
people whining about gay PDA's or "flaunting their homosexuality", heterosexuals do it ALL THE TIME and people have no problem with it.
sexism, homophobia, racism,anti-semitism, pretty much any prejudice at all really.
conspiracy-theorists.
people too lazy to spell or use grammar correctly and l33t speak.
people who whine about election results when they didn't vote. if you don't vote, you have no right to complain.
guns.
the excuse "i have a black friend so it's okay if i say the N-word" and other iterations of it.
the fact that facebook is on EVERYTHING on the internet. (ugh, i despise facebook!)
gamertags/PSN ID's with numbers on the end because the one they want is already taken, you can't even come up with a unique GT/PSN ID?
Call of Duty series
bad gaming trends. like the need for a pass to play online like in Mortal Kombat 9 or Dead Space 2.
not having dlc or developer support for a game.