I must share while I'm thinking about this. (Hopefully will get to my "highlights reel" soon.)
I just read something this morning that I found very interesting, and when I go back and re-watch the scene, it lends deeper meaning to something that is a hilarious throw-away.
It was mentioned somewhere that Sam's body language in the diner scene would seem to indicate that he doesn't believe Dean is Dean until Dean gets third-party acknowledgement. Extrapolation? Sam has been fighting LuciDean hallucinations.
When Dean sits down at the table and starts talking, Sam's reaction is to withdraw. Put the file away, and sit rather blankly. To Dean (and us who are watching through Dean's eyes), it looks like Sam is being pouty and sullen. But then, when the waiter comes and takes Dean's order, Sam brightens a little bit, almost kind of an "Oh, you see him, too!" sigh of relief.
Which means the waiter's affirmation that Dean is a virile manifestation of the divine (one of my very favorite lines in the ep. It's funny BECAUSE IT'S TRUE!) has even deeper meaning. This Dean isn't a hell-induced hallucination. This Dean is Sam's "stone #1." This is a Dean Sam can relate to and interact with. This is the Dean that has been missing from Sam's life for the past ten days. This is the Dean that Sam has been ignoring.
This Dean is Sam's "manifestation of the divine" that will save Sam from his spiral.
Provided Sam can save this Dean from imploding himself.
Oh, Show. You make me flail.