Everyone knows that Friday the 13th, a full moon, and illiteracy cause bad luck. But what of the lesser-known superstitions out there? Don’t be unprepared:

Stepping on cracks will break your mother’s back. Walking on curbs will get on your mother’s nerves. Standing on streets will get your mother stabbed in the face. Concrete in general is bad luck. Asphalt is lethal.

If your ears itch, someone is talking about you. If your eyes itch, they are infected. Sharing contact lenses is bad luck.

It’s bad luck to spill salt. Throw a pinch over your left shoulder into the eyes of your enemy. He will still be your enemy, but now the stakes are higher.

Breaking a mirror brings seven years of bad luck. Breaking a two-way mirror brings seven years of retroactive bad luck. Instead of sitting at the popular table in middle school your family was demolished in a plague.

You jinx your favorite athlete by talking about how good he is while he’s playing. You jinxed yourself when you were born a girl, ’cause they’re pretty bad at sports anyway.

It is unlucky to light three cigarettes from the same match because it increases the risk of lung cancer. That third “cigarette” is a pipe bomb.