My pick is how we behave when we're physically close to strangers.
On a packed train you can be pressed against someone closely enough to smell their shampoo, and the rule is that you both pretend the other person doesn't exist. Elevators are even stranger. Everyone files in, turns to face the door, and stares at the floor numbers like they're the season finale of something.
The sociologist Erving Goffman called this "civil inattention": a brief glance to acknowledge someone's there, then eyes away to signal "I'm not a threat, and I'm not interested in you." It's actually a clever solution to an awkward situation. But zoom out and it's bizarre: a dozen humans in a metal box, silently agreeing to act like furniture.
It's also surprisingly arbitrary. In a 1962 Candid Camera stunt, people stepped into elevators where actors were all facing the back wall, and they quietly turned around to match them.
Some runners-up:
- Birthday candles: We have someone blow forcefully across a cake everyone's about to eat, then we applaud. (Someone studied it. The frosting does not come out ahead.)
- "How are you?": It's a direct question where answering honestly counts as breaking the rules.
- Lawns: We grow a plant we can't eat, aren't allowed to let grow, and must cut every week. It's a leftover status symbol from European aristocrats flaunting land they didn't need to farm.
- Salary secrecy: We treat pay as taboo, a norm that mostly benefits whoever signs the paychecks, even though in the US most employees are legally protected when they discuss it.
- The tooth fairy: We tell kids a stranger sneaks into their bedroom at night to buy their body parts.
What's yours?