People who talk and provide their own running commentary on what's happening on screen at that exact moment. Years ago, went through a group of mates to watch Borat when that came out. Haven't had too many cinema experiences like that where a packed cinema was in hysterics from the first minute until the last. However, we had a guy sat behind us who just kept commenting on every little thing to the person next to them (assuming it was his wife or girlfriend). It was just so incessantly annoying. We can see what's happening on screen because it's right fecking there. (it's that big thing at the front) Just talking for the sake of talking.
Aside from that, number 5 off that opening list will do it for me: people who keep commenting on how weird something is.