In fact, the fear of the number 13 is so common, there is even a word for it: triskaidekaphobia! This fear is so widespread that many hotels and apartments either only have 12 floors or the 13th floor label is omitted, and the floor after 12 is labeled 14. Many airports don't have a 13th gate, and many airplanes don't have a 13th row. In some cultures, the date of Friday the 13th is considered especially unlucky There are many theories about why 13 is considered unlucky.One is that the ancient Egyptians believed that number 13 represented death.