I deal with primary age children who are excluded from mainstream school. They have a variety of problems and we do the best we can to straighten them out. Without humour, we'd go under.
Currently we have a student social worker who comes in weekly for the experience. I told her the old joke, "How many kids with ADHD does it take to change a lightbulb? Ans.: Hey, let's go out and ride our bikes!"
Her mouth gave a small upward twitch and she said, "That shouldn't be funny."
Humour is anarchic and often contains a germ of truth. So it is the first target of the cold forces of repression.
I have been warned.