Because saying "good luck" before a theatrical performance is considered bad luck, dancers say "merde" to each other before taking the stage. Dancers believe this superstition started in 19th-century Paris, when numerous horse-drawn carriages meant a full house. Dancers warned each other to watch their step in the street by saying "merde," the French word for horse droppings.
Dancers' superstitious use of "merde" sets them apart from other performers. Actors and musicians tell each other to "break a leg" before a performance. The penalty for saying "good luck" inside a theater is to go outside, spin around three times, spit on the ground and curse. After this ritual, the offender must knock on the backstage door and request readmittance. In 1921, Irish writer Robert Wilson Lynd wrote an article suggesting that in horse racing and theater, it was highly unlucky to wish someone luck.