Because Confucianism believes that the way of heaven and earth lies in reason and ceremony. The pursuit of external things (including appearance) will hinder our exploration and pursuit of the inner world. Moreover, the body, hair and skin, including appearance, are given by parents, and it is unfilial to talk nonsense. Therefore, Confucianism does not care about appearance, but only about knowledge and morality, which is why it is said that "learning to be excellent is an official". So when writing the word "teacher", cover the word "handsome" with a horizontal line to tell everyone that people's bodies are fragile, their looks are indifferent and their thoughts are eternal!