Why does everyone like to see jokes? What's the old saying?

Why do some people like to see jokes? As the old saying goes, people smile. Laughing at people's eyes shows that everyone likes to see jokes and their work is not that good. Classical Chinese is an article composed of written Chinese language in ancient China, which was used by Han people before the May 4th Movement. It mainly includes written language based on spoken language in pre-Qin period.