Mencius said: "A gentleman has three kinds of happiness, but the king of the world does not share them. The existence of parents and brothers without cause is one happiness; looking up to heaven and not being ashamed of others, and bowing not to be embarrassed by others are the second happiness; Educating the talented people in the world is the three joys. A gentleman has three joys, but the king of the world does not care about them." - Mencius said: "The trouble with people is to be a teacher." - - "Mencius Volume 7 Li Lou Shang"

The former said that "obtaining the world's talents and educating them" is the great happiness of life, and "ruling the world" cannot compare with it. The latter said that liking to be a teacher is the biggest fault and fault in life. The two are contradictory, but both are correct.