I love learning about bits of etiquette from other countries, like how in India you’re supposed to eat food with your right hand (since you do your business with your left), or how in Italy chrysanthemums are only given at funerals. But there’s one tidbit I learned recently while researching the hidden people (elves) of Iceland: don’t throw rocks in Iceland!

The numbers vary, but according to many surveys, a great number of Icelanders believe in the existence of hidden people, essentially a race of elves or other human-like creature that lives in a dimension just beyond ours, and who sometimes are visible to us. Much has been made of how construction has been halted due to the belief that hidden folk live where a road was supposed to go. But other etiquette rules exist, such as never throwing stones, for you may accidentally hit one.

This is good advice in general! When you throw rocks you could hit literally anything–a person, a car, a cat. Throwing rocks is a dangerous hobby, doubly so when there are potential victims that you can’t even see. So err on the side of caution and don’t throw rocks, for the good of all beings around you.

But also because they may start throwing rocks back.