Swiped from another source (can I get a link, Chris?):
"The role of a superior DM is NOT to tell a story
to his or her players. The DM need only provide an interesting and
challenging environment for the players to explore and then administer
that environment totally impartially. Superior players will be able to
create a character-driven, interactive story from these raw materials,
and neither the players nor the GM can tell where the story is headed."
- The Gospel of Papers&Paychecks