Now that i'm not actively playing, and have not been for a while, i've had time to look upon my past experiences. In so doing, i have isolated something intersting: the one kind of player for which i have no tolerance whatsoever. (Jamie, i know you've started in on this subject.. actually i think a lot of the peeves you mentioned add spice to a game itf it's sufficently large. ^_^ But onward..)
I have named this player Tarus FortissiImplicatus. (playing fast and loose with poor old latin there, but read it as Bullish Hero Complex.)
This player is typified in character by a sturdy obstinateness in sticking to his very own script, and bending not a micron for any other character, player, or even the GM. He steadfastly refuses to interact with anyone or any situation that he does not think will lead to the eventual glory that he has plotted out for his character well in advance.
Under some circumstances and played with senstitivity, such a character can serve as an excellent driving force in a campaign. Most of the time, however, such a character is owned not by someone who has the best interests of his fellow players in mind.. he is merely salivating at the change to have a captive audince to witness his fantasy's fufillment.
In a campaign with experienced players, Tarus becomes at best a pawn to be pushed around: at worst an invisible elephant that everyone must avoid running aground on. His most fearsome power, however, is stopping new and more delicate games dead in their tracks.
Tarus can be difficult, even impossible to work around. However, he is not completely hopeless: a crafty player can use him in any number of ways, if the beast is recognized for what he is. So ware, you game-masters: if you cannot avoid him, know him.