The Mysteries of Pittsburgh features many examples of that classic coming-of-age novel character: the wild, unpredictable friend. I have always enjoyed this sort of person, at least for a period of time, and also enjoy a related character (in life and in fiction), the life-of-the-party charismatic friend. People who do things I wouldn't make life exciting.
Michael Chabon was interviewed on Fresh Air today. He was not talking about Mysteries of Pittsburgh when he said this, but it applies to the central relationships in both it and Wonder Boys:
"I guess I'm a more orderly person -- and, therefore, chaos has its appeal."
Me too, Mr. Chabon. Me too.