Role Player, not rule player!
It's all about the creation and progression of an entertaining story. The type that can only be created by multiple points of view stemming from engaged and creative / imaginative players.
The rules are only there as a basis or guideline for helping the story flow and take shape. To me the rules are like the referee in a game of Rugby League. It is there to keep the game moving and fair.
If the game is allowed to continue without hold up (sometimes because the ref lets "slight" rules infringements go because it is in the spirit of the game) than you have a good game.
If the game is frequently stopped to enforce every little rule, than you end up with a long drawn out session that few players enjoy.
The best game of league is usually measured by how little involvement the referee had in the game ... I feel this applies to good RPG sessions as well