Two webcomics just appeared at the same time that illustrate the DM’s Dilemma: Do I kill the party to satisfy my ego or do I satisfy my ego by demonstrating how awesome I am in other ways? Check it out:
Unknown to players, there is a state of mind beyond DMing, and that is writing for its own sake. The players become superfluous; the story becomes of the greatest importance. One wakes up at 3 am and works feverishly for 2 hours, then drags one’s butt through the day’s work. Of course, after a lot of that, DMing starts looking good again!