Christmas Puppy

A person who shows cheer, enthusiasm and excitement around people regardless of the situation, circumstance or obvious lack of concern.

"Our house just burned to the ground."
"OMG we can totally make s'mores now!"
"Why are you such a Christmas puppy!"

or

"Do you know that the radiation from the nuclear bomb that went off is making all of us sick and go bald. The water is undrinkable and we'll die in about 30 days."
"Wigs are totally in style. I've always wanted to glow in the dark so hide and seek is a win win. YES! 30 days of flipcup! WHOO HOOOO!!!!"
"All in favor of killing off the Christmas Puppy say Aye"