Spanish-speaking cultures apparently believe that Tuesday the thirteenth is unlucky instead. Thirteen has been considered an unlucky number ever since Judas became the world's least favourite party guest, so just add your culture's least favourite day of the week and voila - the writing's on the very superstitious wall. It's that simple. Assuming that you're willing to believe in things that you don't understand, of course.
Here's an exhaustive list of bad (note: not remotely unfortunate) things that have happened on Friday the thirteenth. In 1996, Tupac Shakur was pronounced dead - not shot, just the subsequent procedural formality. In 2010, an engineering train decoupled for 13 minutes causing some minor delays on the Tube. In 2029, an asteroid might pass unusually close to the Earth, and I'll admit that this has already inspired several godawful films. Perhaps worst of all, Mary-Kate and Ashley Olsen were born on a Friday the thirteenth in 1986. But that's it. That's all I could find. The invasion of Poland, Hiroshima, Coldplay album releases, Lockerbie, Chernobyl, Diagnosis Murder being cancelled, Fukushima, the assassination of Dr Martin Luther King Jr, the birth of James Corden, Katrina, the Great Fire, Kate Winslet getting married, 9/11, 7/7, a critical mass of people deciding that 24/7 is an acceptable adverb, the Titanic sinking, the Belgrano sinking, Pirates Of The Caribbean - none of these indescribably awful things happened on Friday the thirteenth.
One study estimated that behavioural changes cost the US economy almost a billion dollars each Friday the thirteenth. Ascribing unlucky everyday occurrences to the coincidence of a number and a day is certainly much more fun than accepting responsibility or bothering to analyse causation. But don't forget to buy your lottery ticket today.
