Now that I’ve told you about the superstitions good luck, let’s see where the bad luck came from;

Why is Friday the thirteenth considered to be bad luck?
The number thirteen represents Judas, the thirteenth to arrive at the Last Supper. Friday by itself is unlucky because it was the day of Christ’s Crucifixion. Years ago, the British set out to disprove these superstitions. They named a new vessel HMS Friday, laid her keel on a Friday, and then sent her to sea on a Friday that fell on the thirteenth. The plan backfired: neither ship nor crew was ever heard from again. Then, of course, there’s Apollo 13.

Why is it considered bad luck to walk under a ladder?
This superstition comes from the idea that many early cultures considered a triangle to be a sacred symbol of life. For Christians, a triangle represents the Holy Trinity. A ladder against a wall forms a triangle with the ground, and so to walk beneath it would be to disrupt a sanctified space and risk divine wrath. Even earlier, Christians considered the ladder resting against a wall to represent the ladder that rested against the cross during the Crucifixion, and therefore evil. For this reason condemned criminals were forced to walk under the gallows ladder — the entranceway to eternal darkness. The executioner always walked around it to position the noose.

How did spilling salt become a symbol of bad luck?
As man’s first food seasoning, and later a food preservative and a medicine, salt has been a precious commodity for ten thousand years, so spilling it was costly as well as bad luck. This superstition was enhanced by Leonardo da Vinci’s painting of the Last Supper, within which Judas has spilled the table salt as a foreboding of tragedy. Because good spirits sat on the right shoulder and evil on the left, tossing spilled salt over the left shoulder became an antidote.

So, would you rather believe that superstition is an irrational belief arising from ignorance or fear? Would you want your life to be affected by them? :-p

I’d rather not