If one don't know social behavior, then what will happen to that person?

Social behavior is very much required at least to a basic level which includes how to talk and when to talk or act. You can’t just go on running your mouth and doing whatever you want and not reap the consequences. The consequences depend upon the people you are around. If they are well mannered people, they’d single you out. If they are ill tempered you may get mugged or even worse. It’s all about behaving. I know a few people who go on saying and doing things that aren’t appropriate and they are living a very lonely and miserable life.