The worst allegedly legitimate Christmas song I’ve ever heard is on the Time/Life Christmas Collection (I forget who sings it)
“It’s Baby’s First Christmas” sung loosely to the tune of Rock a bye baby.
The most sappy, sickening song I’ve ever heard. And I LOVE Christmas songs of all kinds. I have dozens of discs.
I heard a rendition of “The Christmas Waltz” that sounded like Frank Sinatra that was absolutely awful because of the way he and the chorus that sang with him changed tempos so much that it sounded like it was anything but 3/4 time - maybe 8/7 or 6/11 or something. There was NO WAY anyone could even attempt to follow the beat, let alone waltz to the performance.