I hadn't seen it until someone here started a thread about it several years ago. In short, the main character is despicable, and when he goes home to visit his parents in Buffalo, you understand why he's that way. I had mixed feelings about it. It was gripping in a way, but uncomfortable. Some people don't like movies like that, but I find them interesting. It's not a "feel good" movie, other than feeling good that I was raised by much better people than his parents.
I have a friend who's a psychology professor. She teaches a course called "Life Span Development," which she jokingly describes as, "101 ways to blame your parents." I suggested that she see Buffalo 66. I don't know if she did.