Why the fear of the number 13?
The Egyptians were the first to develop a superstition for the number thirteen, but for them the number brought good luck. They believed that there were twelve steps on the ladder to eternal life and knowledge and to take the thirteenth step meant going through death into everlasting life. Thirteen, for the Egyptians, was associated with immortality.
Sounds like bunk to me, and although I'm not superstitious-- in my football days I always put on my left sock first, then my right, then my left shoe and then my right-- it was a ritual that somehow made me feel better when I was on the field.
Today I toss the Q-Tip I've just cleaned my ear with from the shower to the waste basket which is about six feet away-- if it goes in I consider the day to be good, if it misses expect the worst. Neither of which seems to make a bit of difference (and I'm about 9/10 on hitting that basket).