The interpersonal relationship in school is the simplest, and there are not many rules to treat people. However, it is very useful to enter the society, learn to understand the world and cultivate human feelings. Things in society are more complicated than those in schools, and there are many rules hidden behind adults' communication. If you want to get along like a duck to water, you must know the rules and understand human feelings.
It's not a bad thing that reality goes smoothly, but a process that everyone has to go through. Only through these experiences can we really grow into independent adults.