What does it take to be considered a 'good' player?

[Baalfrog]

Yeah this is a game with a lot of players, so god forbid to let them have fun, while you sit here and think the only one who needs fun is yourself. Way to go.

Meanwhile in another universe...
Player: Hello GM! I'd like to report an offense!
GM: What is it?
Player: This guy is having fun wrong!
GM: Wrong how?
Player: By not agreeing with my rules on what is fun!
GM: I'm sorry had to deal with this, I will resolve the matter urgently, thank you for bringing this to our attention.

GM: Hello player 2, this is the fun police, I have been informed you are having fun wrong!
GM throws the offending player into GM jail.
Player 2: Excuse me?
GM: Yea, someone died and made that other guy the fun police, so these are the rules now. Have a great day, IN PRISON!

In all seriousness though, a great player also understands that they are not alone in the game and should also tolerate and understand other viewpoints and not dig their own bunkers and be like "OOOH you are not like me, thus i automatically hate you for not agreeing with me on this or that."