I would say that Same Old Lang Syne by Dan Fogelberg is hands down the most utterly depressing "Christmas song" ever written, wouldn't you?
I mean, people have been hospitalized after listening to this song. I mean happy, successful people have reached for a razor blade.
Joni Mitchell's "River" comes a close second, but it benefits from being painfully beautiful as well.
And I generally like the more melancholy Christmas songs--"In the Bleak Midwinter" may be my favorite carol (if I have to have one!)--but when you hear that Fogelberg song on the radio or (worse considering the lyrics) in the grocery store this time of year, it's like, turn it off! Please, for the love of god, turn it off. Maybe he should've set it during Halloween instead.
But here's the thing: whenever it comes on, despite its really borderline cheesiness on top of the whole depressing thing, I am compelled, compelled to listen to it. I can't switch it off.
And it will get stuck in your head. That part where he keens, "We drank a toast to innocence / we drank a toast to time." Well, there you go. Sorry.