i’m 100% stuck between cas loving christmas, the festivity and the way humans cherish each other and do nice things for each other and just generally work a lot harder at being nice to each other, all the colors and the gift exchanges and hot chocolate by the fire!!!
and cas being a huge grumpy scrooge who doesn’t understand how christmas (“Christ mass, dean. Christ mass.”) came to be what it is. he gets tangled in the lights and walks into hanging tinsel and aggressively changes the channel when sam turns on gaudy animated christmas specials about angels earning their wings
but either way, i think the moment cas just melts is when he gets caught unawares under the mistletoe by dean, who just grabs his face and lays the biggest smooch on his lips and, with the biggest, cheesiest grin, says:
merry christmas, cas. wouldn’t be the same without you.