Clowning around as any clown will tell you is an incredibly serious art form.
If you chart the political necessity clowns had in Roman times through to the court jester traditions of Europe you can see they performed a unique role as truth tellers, as people given the social permission to make rulers feel uncomfortable without being killed for it. Something of that tradition survives amongst the comedians of the world who use satire but what has been lost is the intimacy between the rulers and the clown. Today the clowns are on TV and the leaders are in their offices whereas the most useful place for a truth teller to be would be in the offices.
Clowns are also not just about jokes. Their acrobatic abilities and timing are crucial to their fame and success in responding to the audience. The physical stress of performing is just the start for good clowns who can be either silent or speaking, and in many ways the silent ones have the hardest job but the speaking ones must never forget the voice is an instrument every bit as important as the jokes themselves.
It takes years to learn how to clown around without hurting yourself but when you see someone like Lucille Ball and Carole Lombard you can see how worthwhile the training is.