A/N: Is it just me, or are these getting shorter...?
"I have always been... Uncomfortable with that tradition," Cas said, and Dean followed his gaze to the top of the nearby Christmas tree, then chortled when he saw the angel tree topper.
"Yeah, I guess you would be. I don't really relish the idea of being goosed by a pine tree either," Dean grinned, and Cas frowned, "I always preferred the star, myself."
"It was meant to signify Star of Bethlehem that led the magi to Jesus," Cas informed him, keeping pace with Dean even as he looked around the street with interest, "Which is a rather strange habit you humans have, turning pagan rituals into representations of Christianity."
"Welcome to the human race," Dean laughed, clapping him on the shoulder, "I didn't know that about the star thing. What's the angel supposed to represent, then?"
"The Host of Heaven."
"Of course it does," Dean snorted, then his grin grew wider, and suddenly he burst out laughing, practically bent over in the middle of the street and Cas was looking at him puzzlingly.
"I'm not sure how that is funny, Dean," Cas frowned, and Dean wheezed, straightening the best he could.
"S-sorry! Sorry, man, I just- I got this mental image of you on top of the Rockefeller Center Christmas tree and I just- I just-" Dean burst out laughing again, and Cas cocked his head to the side, frowning deeper.
"You and your freaking trenchcoat man, oh god," Dean wheezed, taking deep breaths, trying to get himself under control, "Ha! Sorry! Sorry, I'll stop now. Phew!" he breathed, clapped Cas on the shoulder again, grinning.
Cas was still looking at him with puzzlement, but he seemed to have softened a bit, letting amusement creep into the corners of his mouth.
"You have a very strange sense of humor, Dean Winchester," he commented, and Dean laughed again, restarting their progression down the street.
"Dude, I'm hilarious."