"Like a riot in the heart, and nothing to be done, come ruin or rapture."
Maybe the whisky Dean spends the night slamming back holds the blame for his loss of control when Cas reappears.
Maybe the frustrations of the morning's failed hunt cause him to shove the angel against the wall, his hands fisted in that ridiculous, ever-eternal trenchcoat.
Maybe the mark burning on his shoulder, or the piercing blue gaze — or even the threat of the freaking apocalypse weighing down his mind — makes him lean in and kiss Cas like he needs this to breathe.
And maybe, when Dean abruptly finds himself holding nothing but air, the reasons don't really matter at all.