Yesterday was Friday the 13th. One of at least one and at most three Friday-the-13th-s a year (and the only one this year). There are quite a few theories about the origin of the day’s superstition; the one that seems most reasonable to me is: “13 is an unlucky number*, and Friday is an unlucky day**”. Simple as that!
Weird as it is, there are numerous people who are affected by a fear of Friday 13 (this phobia is called friggatriskaidekaphobia). As for me, I’m not scared of the day and I was actually rather disappointed that nothing in particular happened yesterday. Maybe next time (January 2012)!
*irregular, transgressing the completeness of the number 12
**Friday = Canterbury Tales, Black Friday)