It doesn't really depend on the type of game for me, just whether or not I have friends around when I play. Such as, when I play Dragon Age or KotOR, I can't help but be a good guy and help out all the people who need help. And if I want to do an evil option due to personal gain or having the story in a direction I want it to, then I get scolded by my allies for being such a douche. However, if I'm playing with my friends in a game like D&D, I can't help but take all the evil options just because it is so damn funny. Hell, I'll even do something evil or stupid just to see how my DM reacts. It's the same if my friends are around when I play a BioWare game. I'll go ahead and do all the douchebag options just because it's so damn funny, then laugh at Alistair when he gets all pissy about it.