Alright, so while I was zoned out making subs at work today my brain clicked as to a possible idea as to what is up with Sam, although i'm sure many have already guessed this.
Sam's "soul" or at least of piece of it, is still in hell.
He's a shell right now, only a piece of Sam is really there, it's like he's going on instinct. And what is Sam's instinct? Hunting! ALthough he rejected it for a time, the span in which he did hunt was much longer. He knows to have compassion for Dean, but he doesn't FEEL it. When he got out he needed to turn to someone, finding his grandfather gave him a sense of direction, but didn't help him find that missi