Answer:
Superstition is the irrational believe in supernatural circumstances, and typically those related to fair chance or bad luck, even when such circumstances cannot be explained with a natural phenomenon or rationally but it's still traditionally accepted and very popular.
So builder owners deliberately exclude or miss the 13th floor, generally due being considered of "bad luck", mainly by religious people (in Christianity Judas was the 13th disciple who betrayed Jesus).
Step-by-step explanation: