Why are there five fingers? Because if there were six, the commandments would be twelve.

Why are the glasses open at the top and closed at the bottom? Because if it were the other way around, the bars would go bankrupt. 

Why do nails grow and teeth don't? Because otherwise the neurotics would bite their teeth ”.

Why do fog banks exist?

For students with their heads in the clouds.

Why do mice dance when the cat is not there?

Because the cat is a bad deejay.