The Calvin and Hobbes cartoon from December 13, 1995 made a big impression on me. It's been on my wall since I cut it out of a newspaper that day.

First panel: Calvin is standing in front of a large pile of snowballs. He raises his arms triumphantly.

With 200 snowballs at my immediate disposal, I have no opposition! My will is law! I am omnipotent!

Second panel: Calvin stands there with his hands on his hips, staring straight ahead and grinning wickedly.

Third panel: Calvin's hands are behind his back. He's still looking ahead for any potential adversaries, but his face now bears a thoughtful, quizzical expression.

Fourth panel: Calvin turns toward the audience. Arms hanging straight down at his sides, he states candidly:

How boring.

Bill Watterson, the strip's author, retired at the end of that year. He was the acknowledged master of his art, but wise enough to know to look for new challenges.