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.
Best: Rusty Chevolet. It has more to do with Christmas than the song it's parodying. Also Carol of the Bells, though that sounds less like a Christmas song and more like final boss music.
Worst: Christmas Shoes. It's emotionally manipulative and has a consumerist bend even while trying to be spiritual. Yeah, like Jesus would actually care what shoes you're going to wear when you show up at the Pearly Gates.