There are three levels of people who Harry knows at Hogwarts. He has close friends, people he knows well, and people he knows about or doesn't know. His close friend's values and interests are closely aligned. They are all Gryffindors but Harry, Ron, and Hermione are still different people. There are people he knows fairly well and this group consists of his friends, most of his classmates, and his enemies. They make up different subgroups and he knows a lot of general things about them. The final group is people he doesn't know well.