We need to relax sometimes and humour brings people together. Everyone likes a good laugh. It releases tension, cheering us up, avoiding depression and stress.
It is also an outlet for the imagination, and many creative children have a well developed sense of humour. If people were serious all the time, life would get very boring. It is also important for pompous or ver-powerful people to be ridiculed.
Humour can be cruel, especially jokes about people who are vulnerable, such as minority groups or individuals, anyone with a disability, the tall or short, fat or thin. It is also used by people who cannot argue their case properly, turning serious debate into a joke. Humour can be anti-social: boys laughing at other boys who try hard, calling them "boffs", or girls ridiculing each other for being "fat".