Friggin' Heck: It's Black Friday!

Wikipedia calls the fear of Friday the 13th friggatriskaidekaphobia (I won't even attempt to pronounce it!).
Seems it's a relatively recent arrival: there's no written evidence of a "Friday 13th" superstition before the 19th century, so it's likely a combination of two older superstitions: that 13's an unlucky number and that Friday's an unlucky day.
Numerologists consider 12 the number of completeness (as reflected in the twelve months of the year, gods of Olympus, hours of the clock, tribes of Israel, apostles of Jesus) whereas 13 is considered irregular. A superstition deriving from the Last Supper says having 13 people at a table will result in the death of one of them. It's also been suggested Friday is unlucky because, according to Christian tradition, Jesus was crucified on a Friday.
An interesting Friday urban myth concerns the British navy. The story goes that in the 19th century, the Royal Navy wanted to dispel an old sailing superstition that beginning a voyage on a Friday brought bad luck. So they commissioned a ship named HMS Friday. Her keel was laid on a Friday, she was launched on a Friday, and she set sail on her maiden voyage on a Friday, under the command of a Captain James Friday... she was never seen again. This is just a myth, as confirmed by the definitive listing of RN ships: JJ Colledge's Ships of the Royal Navy: The Complete Record of All Fighting Ships of the Royal Navy from the Fifteenth Century to the Present which does not list any ship of that name. Further, the Royal Naval Historical Branch in Portsmouth has washed its hands thoroughly of this tale.
Many people though do fear a Black Friday. The Stress Management Centre and Phobia Institute in N.Carolina estimates 17-21m people in US are affected. Some people are so paralysed that they don't go to work, avoid flying or even getting out of bed. It's been estimated US$800-900m is lost in business on this day. In 2008 the Dutch Centre for Insurance Statistics said fewer accidents occur when the 13th falls on a Friday...possibly because people are more careful or just stay home.
So - no substance to a fear of Friday the 13th (apart from it being a scary movie!), but if you dread a Black Friday...there's another one this year in July!