What are the most widespread superstitions around the world?

The answer

Superstitions vary enormously across cultures but share a common human tendency to find patterns and causal connections where none exist. In Western cultures, the number 13 is widely considered unlucky (triskaidekaphobia), while in East Asia, the number 4 is feared because it sounds like the word for 'death' in Chinese, Japanese, and Korean. Walking under a ladder is considered bad luck in many Western countries, while in Turkey, chewing gum at night is believed to mean you are chewing the flesh of the dead. In Russia, whistling indoors is said to blow away your wealth. Studies show that superstitious beliefs can actually affect performance through placebo-like effects, with people performing better when they believe luck is on their side.