I pull hard and fast, so I don't want to hear about your drinking problems. Just keep up.
No, we're not doing that boss.
If you go in there, I'm not healing you.
Dude, I'm pulling more DPS than the other two put together, and I'm going for the achievement whether you like it or not.
Do any of those sound familiar? It's that one player in the PUG who thinks he's the star of the show and that everyone else is there to bow down to his demands. More often than not, this ends up being a tank, although anyone who thinks the group can't get along without them is prone to this sort of behavior. The tank thinks that DPS won't dare to kick him because of their long queue times (while they get instant queues). The healer refuses to heal anyone that he personally doesn't seem to like. DPSers can fall into this behavior as well, but this doesn't seem to be nearly as commonplace.
The same thing crops up when you down a boss, and suddenly someone just drops group. They didn't get their drop; therefore, they just leave the rest of you hanging. Has this happened to you? If not, consider yourself lucky (and brace for when it does). Or perhaps you've done it to groups you've been in; if so, remember, this is a group game, and those are four other people want their stuff just as much as you want yours. Be considerate. No single member of a PUG is irreplaceable, and the vote kick button is there for a reason.
How do you generally deal with self-entitled puggers?