My favorite is "I Wish It Could Be Christmas Everyday", because my dad liked it and we always played it while decorating the tree when I was little. It brings back nice, happy childhood memories.
Least favorite by a mile is "Stay Another Day", which is a simp anthem disguised as a Christmas song, and then "All I Want For Christmas Is You" which is excruciating. Actually, I might overrule that and say I hate "Santa Baby" more, because it's just a gold digger begging for gifts.
Worst: The "New Shoes/Momma meets Jesus Tonight" song, which is just miserable and depressing. At least most ConsumeProduct songs try to be at least remotely feelgood, but that one... Anyone who LIKES it, should be on suicide watch. "Oh, I love that song about the broke kid begging to get a discount on shoes because he wants to show his dying mother that he can afford shoes the day she dies. My favorite song! Really brings up the spirits!"
Best: "Make It Christmas Day.", a simple Christian Rock song about praying to Jesus being particularly good to do on Christmas day. I'm not usually much for Christian rock, but it serves its purpose well in this setting.
God, that first one really exists? And I thought the simping love songs were the worst.
If you want to torture yourself, here's the link. It was popular enough to be adapted into a movie.
It's not popular, but I enjoy this version of The Boar's Head Carol.