The following are commonly held superstitions in North America, and a brief background on the root of each belief:
(1) 13 is thought by some to be a bad “omen” linked to a historical bad event (King of France arrested all his Templar Knights in 1307), Norse mythology (a 13th god crashing a 12 god party), or a connection with the Biblical last supper. Today people avoid having a 13th floor and Friday the 13th is thought to be a particularly “bad omen.”
(2) “Knock on wood” is an expression said to avoid some kind of bad thing from happening. This comes from an ancient idea that gods are in trees and to ask that god a favour one had to touch the tree.
(3) Salt over the left shoulder: people think it is “bad luck” to spill salt. Then, throwing more salt over a left shoulder is thought to prevent the misfortune. This might be linked to Judas in the Bible at the last supper, although there are many ideas about its' origin.
(4) Black cat is “bad luck”: In the Middle Ages people thought black cats were the pets of witches and thus a sign of “bad luck.”
(5) Umbrella inside brings “bad luck”: One would insult the sun god if one used an umbrella inside (originating from a time/place when umbrellas were mostly used to shade from the sun).
(6) Break a mirror, seven years bad luck: Before mirrors were invented people thought their reflection was a reflection of their soul, thus people think breaking it results in “bad luck.”
(7) 4 leaf clover: In Irish mythology evil spirits carried 3-leaf clovers while the 4–leaf clover provided protection from those evil spirits.
(8) Rabbits foot: Thought to either be a “good luck” charm of fertility and/or a protection charm against evil.
(9) Don’t walk under a ladder: Or, people think, it will be “bad luck”. Why? In ancient Asia criminals used to be hung from ladders and thus their ghost is thought to be there.
(10) Lucky horse shoe: Used as a “good luck” charm. Comes from a root of ancient Greek mythology, which believed horses to be sacred. When hung over a door, people think it brings “good luck.”
(11) Cross your fingers when you make a wish and people think it will come true, a kind of good omen. Comes from the symbolism of the Christian cross connected to an idea of “good luck.”
Superstition is common around the world, and if your children have grown up in North America it is likely that they have learned at least half of these superstitions from the culture.
May Allah protect us from shirk in all its forms.
May we be guided with knowledge that benefits us.