Have a Little Faith

Castiel has given more for Dean over the years than any one man deserves. And now, after he's ruined all of Castiel's work at building an army and nearly killed Team Free Will's only remaining ally, Dean just wants to know why. Spoilers for the ending of Episode 9x22, beginning of 9x23. Light Destiel. Written for Unattainable Dreams' May Prompt Exchange Challenge.