Because as we all know, human body reaction is controlled by nerves and hormones, and they interact with each other. When people are happy, nerves will cause the body to secrete certain hormones (which have a positive effect on the human body), and when people are unhappy, nerves will cause the body to secrete other hormones (which have a negative effect on the human body), thus affecting people's health. So from a certain point of view, normal people's demand for beauty and the demand for the opposite sex will make people feel different when they see beautiful women, handsome men, frogs and dinosaurs, thus affecting people's health. This has a significant impact on people in adolescence and adolescence.