I spoke to a mate recently about the Fable series, I mentioned that I'd sometimes end a session on Fable 1 or 2 (not 3, don't like that game) by saving it and then proceeding to cause a massive fight in whatever town I was in.
My friend looked at me like I'd gone wrong and proceeded to claim that he's never gone on a rampage in any game, including the likes of the GTA series!
He's in the minority here, right? There's loads of games where you can essentially grief NPC's for no good reason - anyone got any favourites?
Off the top of my head you've got Saints Row, Red Faction Guerilla, Postal, Just Cause, Crackdown and nearly anything by Rockstar (except the table tennis).