Usually humour is based on an unexpected twist. But in America, it is created by staging one of a number of traditional gags, for example:

• A small person or animal hits an adult male in the testicles.
• Someone farts, burps or belches.
• Someone falls down or gets hit in the head.
• Someone belittles someone else with a cruel, original, colourful insult.
• A low status male makes a pass at a high status female with a crude double entendre.

~ Roedy (born: 1948-02-04 age: 64)