It occurs to me that S1 of the show is by far the longest Dean's ever been away from his dad. This living on his own stuff is old hat for Sam, but a whole new gig for Dean. In the background and unremarked upon is the story of Dean's growing independence, to the point that by the end of the season he can disagree with his dad (Dead Man's Blood) and even criticize him, at least by implication (Salvation).