Why is number 13 considered UNLUCKY?

1. Several mass murderers have 13 letters in their names(eg Harold Shipman; Charles Manson; Jeffrey Dahmer)
2. Judas Iscariot was the 13th person to sit at Christ’s table
3. Norse mythology tells of 12 deities sitting down for a banquet, when Loki, the god of mischief, crashed the party, resulting in the death of one of the gods
4. Witches, to oppose themselves to Christian superstition,often make up groups of 13, called covens
5. In a deck of Tarot cards, the number 13 card is called Death

The fear of number 13 is called:Triskaideikaphobia