We thought it was "funny" to think of families with two kids fighting over who gets the mystery "extra" slice.
It's the same damn pizza.
Conversely, when I was in engineering school and working in a group on an project, and we wanted a late-night snack, just for laughs we would often demand that the pizza be cut into a certain number of slices that meant we wouldn't have to fight over the last one, but generally also meant you couldn't just run the cutter across the diameter three or four times.
Easy enough calculation for us engineers, but it was always a treat to watch the arts students who worked at the pizza place try to work out how to slice a pizza into, say, 15 pieces.
(Then I became an arts student, and it didn't seem so funny anymore.)
I’m such an imp that when I worked for Domino’s I’d intentionally cut a pizza into an odd number of slices.
Why do they cut it in eight slices? they ought to cut it in six slices. I mean, who can eat eight slices of pizza?