7. Trolling
Here's one I'm pretty guilty of myself, and it's only a tactic in so far as screwing the game up for your team, so not really, then. If a game isn't going well or I'm not enjoying it, I'll often just start to provoke my own team to get back at them for their shoddy display. Preferred tactics on Halo 4 - which allows team killing - include shooting my team-mates in the back every so often when they're not looking, putting them on edge and making them unsure whether an enemy has opened fire, or one of their own is screwing around. My all-time favourite troll, however, is to get in a Warthog with other players, drive towards the enemy, but then take a left-turn at the last minute and drive towards the nearest cliff. I bail out at the last minute - using my jet-pack to return to land if need be - while the other guys end up falling to their deaths, while I can continue free of punishment by the game. Sure, it's a quick way to have the entire server baying for your blood, but it's totally worth it for hearing their angered screaming.