I don't get angry very often. I get annoyed with people sometimes. When that happens I actually tend to go full on super mega obnoxiously nice to the person pissing me off, sometimes to the point of condescension. I think it's because this tends to make the other person angry without giving them the satisfaction of knowing that I'm visibly upset.
It's kind of a petty thing to do and I've tried to cut back on it. When I played WoW, I removed myself from trade chat because if some douchebag in chat pissed me off (happens a lot, because hello trade chat) I would log into some anonymous alt and send them whispers about "I know you're feeling upset but go take a nap or something and then have a nice day, and don't forget to smile, hon " just because it amused me and I just know it pissed them off. One time some guy called me a name for no good reason and how did I retaliate? By sending him a "Tasty Cupcake" (it's supposed to make your character happy) in the ingame mail once a week for like six months.
I don't know. It's sort of schadenfreude I guess. As I said I've tried to cut back on it quite a lot because it's stupid.