because it is important to be happy. also so you don't start/cause drama that could end up bad. so you want to stay to yourself but still have a good social life.
This is a very complex question because why would someone want to live in a hateful angry world. Living in a peaceful world allows one to fully be able to love themselves and others around them. A peaceful world will allow each other to be able to understand and invite everyone in equally. It is important for ones health and happiness.
