Notice anything missing in the photo below, taken in our hotel elevator?
No fourth floor. Or fourteenth. Or thirteenth for that matter. Asking around a little, I discovered that the fourth and fourteenth are for Chinese superstitions, and thirteen for Western superstitions. Apparently, the Mandarin word for four, pronounced "si", sounds the same as the word for death. And you don't really want to be putting your finger on a button called "death", do you? Unless that finger is skeletal and you're carrying a scythe in the other hand. Amazingly: according to a Reuters report from 2001: "A researcher at the University of California-San Diego has found that deaths caused by heart attacks among U.S. residents of Chinese and Japanese descent tend to spike on the fourth of the month, an increase linked to the psychological stress brought about by fear of the number itself."
(Updated to include fourteenth and thirteenth floors, also missing.)