Superstition. Just read this interesting passage in a book I'm reading :
"They sent her to the 14th floor in the hotel which she always knew was the 13th mislabeled for the people whose idea of the borderline between reality and nonsense was flexible."
Well put, because if it's not labeled the 13th floor then there's nothing to be superstitious about right? Haha
I have to agree that superstitions are funny... But I STILL won't pick up a coin that is tails up for some reason.