Everybody has a “thing.”

Some can’t open umbrellas indoors because it’s bad luck.

Others think a broken mirror causes seven years of tormenting misfortune and some still believe beer before liquor equals never been sicker. Whatever.

But tomorrow is Friday the 13th - the mother of all superstitions and a time when some may voluntarily stay in bed, wishfully waiting for Saturday.

These paraskevidekatriaphobics, the poor souls afflicted with the morbid fear of Friday the 13th, deeply believe detrimental things will happen because a specific number has combined with a day of the week.

And as any scientist or mathematician will affirm, “luck” does not exist. The complicated and long disagreement concerning the term simply states good and bad things happen randomly to people.

But for those that are superstitious, it’s easier to blame bad luck on something other than their own stupidity.

“Never has there been a time in history when we didn’t have to blame our bad luck or thank our good luck to some external force beyond ourselves,” psychology Professor Gary Stollak said.

“People are afraid every single day and that’s why the horoscope is the most widely-read column in the newspaper.”

And a close look at history reveals a chain of events that suggest where the fear for Friday the 13th comes from.

Joe Nickell, a researcher, investigator and columnist for Skeptical Inquirer: The Magazine for Science and Reason, said in order to understand the number 13, one has to understand the number 12.

“The number 12 has traditionally represented completeness,” he wrote on a Web site. “There are 12 months of the year, twelve gods of Olympus, 12 signs of the zodiac and 12 apostles of Jesus. Thirteen exists just one digit beyond 12, and is symbolic of the first departure from completeness or the initial step toward evil.”

David Emery, writer and chronicler of urban folklore, also has insight on this phobia at www.urbanlegends.about.com. He examines spine-tingling theories and superstitions like “It’s been said