Analogy of RPG GM and game designer

An RPG gamemaster (GM) is more or less responsible for the entertainment of the group--if they're not entertained (overall) they won't continue to play. The players are also responsible, but not nearly to the same extent, each is mostly worried about himself. The GM has a lot more influence.

He's not there to be an opponent, he's not there to enjoy himself though we hope he will. He's not the opponent of the players, he's the neutral referee/facilitator.

The game designer has the same situation and responsibility. he should not be designing a (commercial) game to enjoy himself, but to enable players to enjoy it. He is not the opponent of the player, not there to laugh at the players and their frustrations. He's there to entertain the players.