Reading an old thread on the Hero Games discussion boards, I came across this post from a contributor with the handle RDU Neil (post trimmed slightly).

Game Contract… I call it a social contract… and it is the most integral concept in role playing. It is the agreed upon parameters for what is acceptable behavior by all players (GM included). It is integral to creating a consistent/coherent “shared imaginary space”…

The social contract is absolutely essential for determining “what is fun” because it isn’t just about you. It isn’t just about C– deciding what is fun and what isn’t… what will be run, and what won’t. It is the group consensus about what is fun… about how people communicate in the group… about what is acceptable for the current game (western vs. star wars), etc.

Without a social contract or game contract… you don’t have a game at all.

Granted, most people don’t consciously think about such things… but that is why problems and arguments and immature “me vs. him” kind of stuff comes up… because nobody has examined the true social dynamic going on, and nobody is understanding that the root cause of the disfunction is a violation of this social contract.

Neil’s right, of course – and particularly about the fact that we don’t usually consciously think about such things, causing disfunction (which causes unhappiness with the game and/or group).

This is one of the reasons Chris Chinn’s Same Page Tool is so valuable. Used as Chris intends it (as a basis for group discussion and – hopefully – eventual agreement, rather than as a questionnaire to be filled out by individual players), it helps bring these unspoken issues to the forefront, and gives everyone, including the GM, a chance to talk about them before the game even begins.