That moment when you realize that the other reindeer didn't like Rudolph until Santa chose to use him, they didn't treat him nicely until it was cool to do so, not because of his personality, or interests.
They refused to accept him because of his differences, until he managed to do something great with it.
That had that Christmas eve not been foggy, he probably would've been a social outcast the rest of his life.
The moment you realize, that the story of Rudolph the red nose reindeer, is pretty depressing.
Merry Christmas :)