"One day last year, an engineer and I went to a pizza place for lunch. The engineer told me he wasn't very hungry, but he said he was going to get the 12-inch medium instead of the 8-inch small—because the medium was more than twice as big as the small, and it cost only a little bit more. This sort of blew my mind."
Although the prices are quite similar...
A 12-inch pizza is more than twice as big as an 8-inch pizza.
A 16-inch pizza is four times as big as an 8-inch pizza.
So, always order the bigger pizza! Math!
P.S. Did you hear that the Oscars pizza-delivery guy got a $1000 tip?
(Photo by Todd Coleman. Via Kottke)