The earliest known source of irrational fear about Friday the 13th supposedly comes from a tale in Norse mythology. Friday is named for Frigga, the free-spirited goddess of love and fertility. When Norse and Germanic tribes converted to Christianity, Frigga was banished in shame to a mountaintop and labeled a witch.
It was believed that every Friday, the spiteful goddess convened a meeting with 11 other witches and the devil—a gathering of 13—and plotted ill turns of fate for the coming week. For centuries in Scandinavia, Friday was known as Witches’ Sabbath.
Man, I tell you this: If someone named me Frigga, I'd be out for revenge, too.
Apparently, in modern times, folks still have a stick up their ass about Friday the 13th. It's estimated that between $800 million and $900 million in business is lost because people are afraid to leave the house, drive or use their fucking brains.
Here's something to really fear: On Friday, April 13, 2029, the asteroid 2004 MN4 is supposed to make a close encounter with Earth. We're doomed, for sure. *