"Man, power gamers are hitched tighter than a librarian's miniskirt."

...

"The f*ck you lookin' at?"

don't get ut either.
Cory? seem like the guy who "play to win" not caring much about the roleplaying aspect, i think his kind his the most common munchkin. even at their worse, they're not really preventing others player from having fun.
Luke? clearly the type who is in the "i just made a crazy OP character because i could do crazy stuffs this way". you can really have some fun playing with this kind.
Now DM? the type who would create a character that'll go on lethal PvP with the other just for the heck of it. that's ruining the fun for the other player.
Guess it's still better than people who are jerk IRL around the table and not just in the way they play...