I don't know what it is, but I cannot visually process the symbols for the "door open"/"door close" buttons in elevators.

I see someone jogging to catch the elevator right as the doors are closing and I'm panicking trying to figure out which button to press because if I get that wrong I look like a huge asshole.

Swapping out your outlets and light switches gives you the rare opportunity of discovering which wiring is tied to which circuit breaker.

The results may surprise you! Like an outlet on your first floor on the same circuit as the lights in the basement. Never would have guessed that one.