Castiel lets Dean's anger soak into him like rain, like hot shower water because he deserves it and he thinks he might be happy to have it. Dean's anger is a sign that he cared, once upon a time, a sign that he hasn't lost the will to fight and if anything at all Castiel is glad that Dean found it again. Whoever gave it back to him -Sam, Bobby, someone Castiel didn't even know- whoever it was, to them Castiel is eternally grateful.

"You once told me you didn't care about the bigger picture. You only wanted to save a pair of wayward orphans." Castiel touches the hilt of the knife at his thigh, adjusts the strap around his jeans. "I thought that would be a good place to start."

It was alarming, how often Castiel was beginning to look to Dean's words instead of the word of the Holy Father, but with no more Grace to preserve and probably no soul to be damned, Castiel thought it was all right for him to abandon God as his god. Dean's words always struck a deeper chord in him anyway. And well, with his perception narrowed and his ability to protect severely diminished, Castiel was beginning to understand why Dean never seemed to grasp the bigger picture as he had.

Two wayward orphans sometimes could mean more to a person than the entire world, in certain circumstances.