With this sensation of triumph dampening the displeasure Stark woke up with, he can magnanimously allow himself to grin some for that response. He rolls the window down enough to flick ashes out, and shifts restlessly, trying to find room in the floorboard to fit his long legs. As entertaining as it might be to quote at this guy for the remainder of the journey, there are other things to be addressed.

"You really thought I was a demon?" It's very little a question; obviously, Winchester did think he was a demon, what with the containment circle. Presumably he knows better now.