I refuse to play Global Thermonuclear War.
It's the only way to win.
May I interest you in a nice game of Chess?
More on topic, I won't play a game where you are genre-baised incapable of obtaining a Disney ending. Also! I don't play games where you as a player suck.
Escapism and such.
Similarly, I don't play high mortality rate games.
I got a strong preference to fantasy, often high fantasy. Ero and the like games might not suck so bad for me if they weren't, in my experience, all pretending to be a different genre and then degrading to really bad crosses between Days of our Lifes and creepy fetishes.
Also, I hate games that rely on randomly killing/maiming/rapeing your friends on bad dice rolls. I'M LOOKING AT YOU WEREWOLF. Similary, I dislike games that rely on out-thinking your friends, like political ones and mysterys.