Mmm, I love the slow slide into more for them in this one; I love the story about Sam calming himself down when he was at college; I love what Dean means to Sam here, and I love how important Sam's innocence/scarlessness/etc is to Dean, and that he wishes he could have kept him like that. I love that this is inevitable for them, and Dean can't even want to stop it, and it just works for them. Lovely, lovely stuff. =)