Everyone wants to have a happy life. In people’s imagination, happiness means a happy family, a smooth career, harmonious interpersonal relationships and good health. Generally speaking, if a person has a higher income and is in a higher class, his happiness will also increase accordingly. Harvard University spent 76 years conducting a Grant study, which began in the late 1930s. At that time, 286 experimental subjects participated in the study. From adolescence to old age to the end of life, the researchers struggled to pursue the answer to the question. It was not until a few years ago that they finally came to the experimental conclusion , and this conclusion…