What makes Friday the 13th unlucky?

Today is Friday the 13th, normally we'd be happy that it's Friday, but Friday the 13th is considered an unlucky day, but why?

The number 13 is considered unlucky for many reasons. Friday is not considered unlucky for any particular reason but as of the 19th century, Friday the 13th was considered unlucky.

Impacts

In the United States, there are estimated to be between 17 and 21 million Americans affected by a fear of this day according to the Stress Management Center and Phobia Institute in Asheville, North Carolina.

Some people are so fearful of Friday the 13th that they avoid their normal routines of doing business, taking flights or even getting out of bed.

About $800 to 900 million USD is lost in business on this day.

Is Friday the 13th actually unlucky?

The number 13 isn't considered unlucky in all cultures. And as for Friday the 13th, there is no credible evidence that this day is any more unlucky than any other day.