Why is the number 13 bad luck?

There are a few theories about why the number 13 is considered bad luck. One popular theory is that it has to do with the Last Supper, in which there were 13 people present.

Another theory is that it has to do with the fact that there are 13 lunar cycles in a year. However, the most likely explanation is simply that it is an example of superstitious thinking. People have a tendency to associate bad luck with things that they cannot control, and the number 13 is an easy target for this type of thinking. Regardless of the reason, the number 13 has become synonymous with bad luck, and there's no shortage of people who will go out of their way to avoid it.