WHY? Why does getting hit by bird poop bring good luck? Wearing three keys together is supposed to unlock health, wealth and love.

A horseshoe hung with the curve facing down is supposed to catch luck. Some lucky charms have some symbolism to them or some strange logic behind them. Where did they come from? Why are they lucky? And who is dumb enough to believe in them? I’m talking about random items that are supposed to give you good luck. I’m not talking about the cereal, of course, that would be just silly.