It’s funny because it’s true.

A man walks into a bar and sees a nun spinning wool behind the counter. The man asks for a drink, but the nun just obliviously keeps on spinning. The man waits a few moments and asks for a drink again, but she’s just keeps on spinning. The man asks a third time, louder, but she just goes on spinning obliviously. Not sure what to do, he shouts at her to stop spinning and pour him a drink. The nun looks up and says… “This is becoming a habit.”