I like the game for the fact that it's fun and it uses real weapons instead of science fiction. The fact it has a large community allows for varied game play as well.
Alas, there are a few mechanics of game play that were not meant to be exploited but are all the time. As such, it ruins a game that could have been much better. But Infinity Ward had to be lazy assholes and do as little work they can in order to cash in on their previous huge success.
The one thing I hate most, though, is people who use Marathon Pro, Lightweight Pro, and Commando Pro with a Tac-knife pistol or dual 1887s or Rangers and do nothing but run around and stab people. Every time I play I get one of those bastards who can lunge 6 fucking feet past my Claymore to stab me even though I have shot three rounds with Stopping Power into them, and all they get is a heartbeat sound and flashing red screen, if anything at all.
Fucking. Bullshit.