BO2 and MW3 overall. The result of developers who listen to statistics instead of previous successful game traits and common sense.
Other than that, oldschool camping. Like, the kind where you camp a room/location with traps over a high traffic area, is the kind that I can't stand. Unfortunately, in BO2 everywhere in these maps are basically high traffic areas. Camping like that instead for the defense of an objective is probably my least favorite thing, ahead even of hacking.
Xbox Live: Eighth Element || PSN: Echo_Resonance ~TL;DR? Don't care.~