You just think it's useless. Etiquette, decency and shame tell us that man is a higher species, and the difference between him and the beast is that he often ties us with the beast, and he doesn't wear clothes in the street? Bite each other casually? Without the rule of law and moral constraints, we will become animals! With the existence of these, human beings will be more developed and the survival of the fittest will be eliminated in nature.