Funny story about this episode. My dad was watching it with me and had just stated that he hated it when Dean turned around looking like a chipmunk. To my total surprise, my father burst out laughing and had trouble stopping. Ahh... family bonding...
All he ever wanted was his brother. He didn't need to know how his brother saw him.

He fought with Sam at every turn, watching the younger man get mad. By the end of the hunt, though, Sammy was more guilty than angry. Dean could live with that. If Sam felt guilty, he would stick around a little longer and try to make up. He would try to make it better, and Dean would make it hard. It was because of this that he knew he was selfish.