Nobody really knows why we laugh, but what we do know is, when we find something funny, it triggers a nerve impulse in our brains, which sends an electric signal through our body, and that makes the diaphragm flutter up and down, which creates the sound of laughter - and also makes it very painful and awkward if you're having sex at the time. As children grow older, their sense of humor becomes much more sophisticated, which means they only ever laugh if they see someone hurting themselves. To make a kid laugh, you just need to walk into a door, or fall into a fireplace, it'll make them chuckle and snicker and snort - and anything involving a groin and the corner of a coffee table is a winner. Parents have been known to whack their heads against the bathroom sink for seven minutes straight, just to hear their children make a single guffaw - and for the rest of the day they can't put their tongues back in their mouths. There was a Nazi called Goering.
Puns are that easy.
Or you could use repetition as a way of getting a laugh, but it doesn't produce a very high grade of humor. Or you could use repetition as a way of getting a laugh, but it doesn't produce a very high grade of humor. It's very versatile. But if you get into trouble, you can always resort to some cheesy high-jinks. The exception, of course, is the hysterical joke about Stephen Hawking and how he got an attack of diarrhoea in his wheelchair right in the middle of an Easter service.