Before this post is made redundant...
On 7.21, Dean Winchester, and the stresses of fake parenthood.
In the film "Searching for Bobby Fisher," a brilliant young chess player, maybe 10 years old, on the verge of winning a championship match, bows out. You see, he can't stand the idea of winning if it means someone else has to loose. He doesn't want his actions to result in another kid getting hurt. This is pretty much Castiel's headspace right now. Traumatized by the repercussions his actions have had on Sam, Dean and the world, he chooses inaction. Observation. So on the one hand, because of his experience, he can claim a greater understanding of the Universe, but on the other hand, he's now even more afraid of taking part in it. And while a big part of this decision has to do with his remorse for hurting Dean, it's basically the opposite of what Dean needs from him at this point.
What Dean needs is for Cas to once again be equal or greater than him. Not lesser than. He needs that strength and force of a terrifying Angel at his side that Cas once so willingly gave him. So much more than apologies and explanations, Dean needs for Cas to stand next to him, support him. Because right now, he's barely supporting himself.
Only recently has Dean been able to take a step back from the stresses of worrying about Sam. And knowing Dean, he probably hasn't totally stopped. So many of the friends Dean's leaned on in the past have been lost to him: Lisa, Bobby, Cas. And now, where he might have regained one of those friends, he essentially finds a child. Another helpless being to look after. It's understandably frustrating. Frustrating in the sense that he can't seem to make Castiel understand that the best way to show him he's sorry would be to jump back into the fight with them. Because that's what Dean needs most right now, support. And yet all Cas offers him are pranks and games, riddles and magic tricks. Even if Cas' intention is to try and make Dean understand his decision to remain passive, his way of doing so comes across as infantile to Dean. Because Dean refuses to treat life as a game. He refused to accept it from Zachariah, and he refuses to accept it from Cas as well. For Dean, it trivializes what they do, the sacrifices they've made. It turns their life into that greyhound race with the little plastic rabbit at the end. No wonder Dean gets angry and throws the board game off the table. To simplify everything that's happened down to a game of Sorry! is insulting to Dean. To sit there and talk in metaphors when they need to be out there fighting, is a frivolous waste of time.
Desperate for help, Dean is instead forced into a paternal position yet again. Fighting extreme stress and exhaustion, he finds himself sounding like his father. And not in a good way. In the car on the way to the cabin, Cas draws attention to it, asking him why he's angry, and Dean quickly reels his emotions in. But it's clear that the pressure is rising, the responsibilities are weighing on him even more heavily than ever, especially with Cas and the other angels to worry about, on top of everything. The mask is starting to crumble. Back in 7.11 Dean was trying so hard to be that "Dear Mr. Fantasy" of the closing scene, the one who holds it together for everyone, makes everyone else feel better, feel like things will be okay. But there's only so much responsibility a person can handle. Dean needs help, and he's not getting it. And so, like a parent who works too many hours and has too few friends and family to help, who's forced to sleep in fits and starts, who probably wonders how the fuck they ever got to this point, Dean's starting to visibly crack.