Demand curves slope downward incentives matter

The typical all-you-can-eat buffet customer serves herself more than 4 pounds of food—much of which winds up in the trash, he said. The by-the-pound guest, in contrast, serves herself 1-to-2 pounds and the more she takes, the better it is for the business.

Here is the longer story (WSJ), with additional points of interest, via the estimable Chug.