Today is Friday the 13th which is considered unlucky by many superstitious people in western culture. But why?
Well, the number 12 is considered a “perfect number” by mathematicians, and adding one more could be considered making a perfect number unlucky.
Also, it is believed that Jesus was crucified on Friday and several late 19th Century English language sources relate the “unlucky” number thirteen to the Last Supper where Judas, the disciple who betrayed Jesus, was the 13th to sit at the table.
So the combination of both Friday and the 13th came to become considered an unlucky superstition, particularly in the United States and the United Kingdom.
The Friday the 13th superstition is so prevalent in the U.S. that many hotels and high-rises skip the 13th floor altogether.
Some people irrationally fear Friday the 13th so intensely that they suffer from the psychological disorder friggatriskaidekaphobia which is a combination of the fear of the number 13 (triskaidekaphobia) and the number 13 falling on a Friday (from Old Norse Frigg).
In American pop culture, the rise and zenith of the association of bad luck to Friday the 13th happened in the 1980s due to the slasher film series Friday the 13th where Jason terrorizes teens at Crystal Lake while wearing a hockey mask.