Dean deserved to parrot Cas' speech in 6x21, "Dean, I do everything that you ask. I always come when you call, and I am your friend. Still, despite your lack of faith in me, and now your threats, I just saved you, yet again. Has anyone but your closest kin ever done more for you? All I ask is this one thing." (Cas' speech is kinda manipulative, especially since one point is a blatant LIE lol).
Castiel was spiralling too bad to be stopped like this, but the (true) words of everything Dean did for him (opposite to the angels) would have haunted his thoughts and Godstiel would have killed allllllll the angels because of it.
