I'm doing stuff for finals and thus don't have time to do a full episode review, but...
My goodness, what delicious Dean/Cas material, but PEOPLE ARE SO MAD AT DEAN. D:
I can't be angry at any of them. I seriously can't. I see Castiel's actions as justified, and I see Dean and Sam's reactions as justified.
Castiel didn't see any other option to take in order to prevent the apocalypse. The problem is that his solution runs the risk of being just as destructive as Raphael's apocalypse.
As for Sam and Dean, Cas lied to them repeatedly and broke their trust, and he made the decision to go after purgatory without informing anyone. Cas has been extremely proud of what he's done (raising Sam, standing up to Raphael), but he's clearly having doubts about his own path and isn't wavering from what Dean sees as a threat.
And the clincher that made me kinda really like this episode a whole lot? Cas's dialogue made it such a central issue throughout the episode that... well.
PRIDE BEFORE THE FALL.
"Pride goeth before destruction, and an haughty spirit before a fall."
*ducks and runs*
Told ya I would get caught up before the end of the season. :P