Set at some point during Season Six, no spoilers.
Dean knows he’s being a dick where Castiel’s concerned. But knowing something and knowing when to stop doing that same something have never been things he’s particularly good at. Like a dog with a bone he just can’t let some things go. And giving Castiel some slack seems to be one of those things.
It doesn’t matter that the angel will always try to be there when Dean needs him to be, he just keeps thinking about all the times Castiel isn’t there when he calls. It doesn’t matter that Castiel is going through some kind of civil war upstairs (a war Dean hasn’t bothered his backside to ask about, to ask how Castiel’s doing, how he’s coping), all that matters is that he’s not down here doing his damndest to help him, him and Sam. It doesn’t matter that he all but forgot about Castiel during his time playing house with Lisa and Ben, it doesn’t matter that he all but dismissed the quasi-relationship he’d had with Castiel before the apocalypse ended and everything just… well, everything else just ended too.
The more he thinks about it though, the more he knows he’s the reason the everything else ended. And maybe that’s why he keeps lashing out. Why he keeps demanding and taking all that he can from Castiel. Maybe he just wants a reaction. Maybe he just wants to know that he hurt Castiel, that the angel is at least a little bit pissed at him for what he did, that Castiel even cares. But Castiel is as amicable as he’s ever been and aside from a few ruffled feathers doesn’t even blink when Dean snipes at him, needling him with ingratitude and commands him to do better, to try harder, as if Castiel is something he owns, an angel there only to do his bidding and to be there at his every beck and call.
He hates himself for it, for doing this to Cas. All he wants is a reaction, an acknowledgement, like a boy tugging the pigtails of the girl he likes, Dean just wants Castiel’s friggen attention. And so he goes about it the only way he knows how. The only way he knows will eventually wear thin Castiel’s stoicism and draw forth a reaction.
He acts like a complete and utter dick.
♥ this piece inspired by Dean’s dickish behaviour towards Castiel, repeat listenings of Wicked Game by Stone Sour, and the pressing urge to sleep preventing me from taking this piece in the “Castiel pinning Dean to a wall in protest and having angry sex with him” direction I’d been hoping to take it. Oh well, c'est la vie! ;D