Why is Friday the 13th Bad Luck?

If you're one of those people who avoid traveling, going to work, eating in a restaurant or signing important documents on Friday the 13th, you have paraskevidekatriaphobia. There is no need to call the doctor. It means a fear of Friday the 13th. Here are some superstitions about Friday:

• Never change your bed on a Friday as it will give you bad dreams.
• If you start a trip on a Friday, you'll have misfortune.
• Cut your nails on a Friday and you cut them for sorrow.
• If ships set sail on a Friday, they will have bad luck.
• Friday is the witches' Sabbath.

Here are some superstitions about the number 13:

• 13 is the Devil's Dozen.
• Should 13 people eat dinner together, all will die within the year.
• Just as many buildings don't have a 13th floor, going right from 12 to 14, many cities don't have a 13th Street or 13th Avenue.
• If you have 13 letters in your name, you will have the devil's luck. Don't believe it? Count the letters in these infamous names: Jack the Ripper, Charles Manson, Jeffrey Dahmer, Theodore Bundy and Albert De Salvo.
• There are 13 witches in a coven.

It's bad luck to:

• Begin a new job or a trip
• Cut off both ends of a loaf of bread
• Flip your mattress
• Put new shoes on the table
• Leave your hat on the bed
• Walk under a ladder
• Pour water on a windowsill
• Plant potatoes
• Lean a broom on a bed
• Open an umbrella indoors
• Do housework
• Wear new clothes
• Cut your hair
• Sneeze to your left side
• Have a black cat cross your path