Photo Credit: Flickr Creative Commons

Ordinarily, the 13th of the month is just another day on the calendar. However, when it falls on a Friday, as it will tomorrow, the day takes on a whole new significance. That’s because Friday the 13th has a reputation for being unlucky. The unfounded fear that affects over twenty million people in the U.S., and many more worldwide, is so serious, that it is considered a medical disorder that goes by the names friggatriskaidekaphobia or paraskevidekatriaphobia.

People who suffer from this affliction experience symptoms that range from mild anxiety to a nagging fear that something bad is about to happen, to even full-blown panic attacks. For those that work in injury-prone industries like construction and shipbuilding, the fear often becomes a self-fulfilling prophecy. This, of course, makes them dread the day even more!

So how did the day get its bad reputation? Some of the notoriety can probably be attributed to the release of the first “Friday the 13th” movie in 1980. However, for many the fear began long before the hockey-masked villain of that tale, Jason Voorhees, made his appearance.

Last Supper by Leanardo Da Vinci (Photo Credit: commons.wikimedia.org)

Some believe it all begins with the fear of the number 13 regardless of where it appears. According to University of Delaware professor Thomas Fernsler, the reason people hate the number is because it follows the nicely rounded and ‘safe’ number 12. There are after all 12 months, 12 zodiac signs, 12 tribes of Israel, 12 apostles of Jesus . . . So on and so forth.

Donald Dossey, a folklore historian attributes the fear to ancient times when the Vikings lived in Scandinavia. According to one popular myth, twelve gods were enjoying a quiet dinner party in their mythological heaven, Valhalla, when a god called Loki (of the Thor movie fame), strolled in. The uninvited 13th guest caused havoc and even instigated Hoder, the blind god of darkness to kill Balder, the god of joy and gladness. According to Dorsey, this is the reason many people shy away from hosting dinner parties with 13 guests. In Paris, some businesses even go as far as 'renting' a special 14th guest or quatorzieme.

Photo Credit: Flickr/Creative Commons/Flavia C

Friday gets a bad reputation because according to the Bible, that was the day Jesus was crucified. Though the date was not the 13th, it was right after the Last Supper, whose 13 guests included Judas Iscariot, the apostle that betrayed Jesus. Some biblical scholars believe that Eve tempted Adam with the forbidden fruit on a Friday as well. Nobody, however, knows what the date was. The one unfortunate event that is thought to have occurred on Friday the 13th is the slaying of Adam and Eve's son Abel, by his brother Cain.

Given the widespread paranoia, it is not surprising that many people avoid getting aboard airplanes or making big purchases on Friday the 13th. Some are so afraid that they don’t even leave their homes. As a result, American businesses lose between $800 - $900 million USD every time the 13th falls on a Friday. Fortunately for them and those that fear the day, tomorrow is the first and last time we will encounter the date and day combination in 2016 — So try and enjoy it, if you dare!

Resources: wikipedia.org, businessinsider.com, history.com