I can't stand FPSs or any game involving war/guns/military or the sort of tactics involved in shooters. The setting is boring, the play style is too difficult for me, uh... yeah.
I'm an avid loather of sports IRL, so of course I dislike the genre of games that goes with it, though my dad likes golf a lot, and admittedly I had a lot of fun playing some of the Tiger Woods games on the PS2 with him and my bros several years ago, till it became evident I sucked at those as much as any other video game.
I'm also not a fan of RPGs in general; never played any Final Fantasy games, save for that Crystal Chronicles thing on GameCube (so sue me). Never played any of the other 'classic' RPGs people like so much either. I guess the play style just doesn't suit me.
Also, MMORPGs. Forming alliances or groups with random people on the interwebz as a requirement for getting the 'full experience' of a game is not my thing. I just want to adventure on my own, dangit, and without having to level-grind just 'cause I don't wanna talk to weirdos or get picked on 'cause I don't 'play my class right'. If there was an MMO where you can be whatever you feel like and change your mind without making more characters, instead of being bound by classes; where you can pick up any number of skills/trades as you please; where you can enjoy the game without having to have friends that play it or team up with random people... Yes, I know the whole point of them being Massively Multiplayer is so you play with other people, but what I like about them is the huge worlds to explore, like a humongous action-adventure game, only you can't get by just by talking to NPCs. >.>;;