Willpower is Important.

12:01pm: "You know, I'm gonna skip the pizza today."
12:02pm: 'pizza's here!' email arrives.
12:03pm: I'm in the cafe, teeth gnashed, eyes rolling in the back of my head.
12:03:30pm: All the slices are cut in half, like at kids parties.  "I don't DO kiddie slices," I sneer.  Then consider: "Maybe this is a sign, that I really SHOULD skip the pizza today."
12:03:40pm: Inhaling kiddie slices.