I could say "Grandma got run over by a Reindeer" but that would be too easy.

All of them suck lol

Any Xmas song sung by Bing Crosby

O Holy Night. I don't like the tune. It's exasperating.

I wrote an adult Santa Claus song, as payback.

You better watch out
You better get saved
You better, before it is too late
Jesus Christ is coming to town

He has a big book
Unless you forgot
It tells who is saved, and who is not
Jesus Christ is coming to town.

He knows when you are sleeping
He knows when your awake
He knows if you are left or right
Save your soul, don't masterbate

You better repent
Don't fornacate
For hell is no hot night club
Jesus Christ is coming to judge.

He knows when you are lying
He knows when your a cheat
He knows when you are gay or not
So stop! Before the heat

The trumpets will be blowing
Then we will all be knowing
We will all be finally going
For Jesus Christ is coming to town!!!

Santa Claus is coming to Town
Scared the hell out of me, as a child.

Feliz Navidad. Ugh!

Oh ..shit. I avoid them like the plague. So much so, I refuse to consider the question ...I'll read the comments, though..

I rewatched the Rudolph animated show a few years back and was shocked at how much of a dick his dad was! LOL And I watched it every year as a kid; so did my daughter!

Agreed. That's a pretty bad message. Especially for reindeer. But I think honorable mention should go to "I Heard the Bells on Christmas Day." Musically it's pretty. Lyrically, it's depressing as shit. It paints a dismal picture of mankind's cruelty to one another. Then it ends by saying, "cheer up, God's alive, therefore "right" shall prevail. No evidence, of course. Just have faith. (Festive! Right?) There are a ton of Jesus-y Christmas songs, of course. But that one has always been particularly grating to me.

Anything Christmas related that Michael Bolten ever recorded.

That, and The Christmas Shoes by New Song. Although Patton Oswalts take down of it is freaking hilarious.

Santa Baby is my favorite.

Carol of the bells. This carol alone proves the absence of god, nevermind the truly awful covers by third rate boy bands. Ugh!

I used to hear one on the student station at nc state, and the main chorus line was "have a merry christmas or i will kill you!!" makes me laugh to this day.

Whichever one I can hear playing, whether audibly or in my head is the worst at any one point in time.

You have attracted an expert. Working in a grocery store in my retirement to keep busy I am inundated with xmas music all day. Jimmy Durante's version of "Frosty the Snowman" and "Holly Jolly Christmas" with Burl Ives. All xmas songs are annoying but hearing about 30 on a continuous loop for 30 days straight, these two are my most dreaded. I would rather hear kittens crushed under the wheels of a big rig, and I really LIKE kittens.

I really like christmas songs, ironic though it may be. The one I hate the most is Bruce Springteen's version of Santa Claus is coming to town.

There are a few I can't stand (Carol of the Bells being the worst). I think it's kind of funny that a few of the most popular were written by Jewish composers:

Xmas songs, Jewish writers

“Do You Hear What I Hear”
“Silver Bells”
“The Christmas Song”
“Rudolph the Red-Nosed Reindeer”
“Holly Jolly Christmas”
“Rockin’ Around the Christmas Tree”
“Winter Wonderland”
“It’s the Most Wonderful Time of the Year”
“Let it Snow! Let it Snow! Let it Snow!”
“White Christmas”

That list is taken from this article from the Toronto Sun:

Any song that goes on about angels, god, the lord, the baby jesus, the mighty king, the wise men, mary and joseph, any thing religious. automatic turn off.

Holly Jolly Christmas.

O Come Oh Come Emmanuel...such a downer to listen to...lol

Since I come from a Different Culture. In Puerto Rico the Jibaro Music is only Played during the x-mas season. Jibaro will be like the american equivalent of hillbilly country. But in Puerto Rico the lyrics often enough has nothing to do with x-mas... a lot of "double sense" and "sexual connotations" masquerade for the season. Is important because we have the custom of doing "asalto", we start the season after thanksgiving and continue until 8 days after 3 kings day on January 6th. Those 8 extra days are called "Octavitas". The deal is we go after everybody goes to sleep and round up a posse., guitars, congas, all kinds of instruments and wake up houses. Sometimes we inform ahead of time the target house so food and alcohol is available, we are there for 30 mins to an hour and we take off for another house... all the way until the last house around 4:30, 5:00 AM, they need to cook us Breakfast... Good Vegetables, Heavy Duty Gumbo. Drinking. Is a Moving Party. Lots of embarrassing moments like going to a christian house were there is no alcohol. I had seen 20, 30 people or more at times the target house join in to accompany. The songs about x-mas get combined with the others that become radio hits talking about cleaning a widow garden patch or farm, a candle being blown by the breeze... all kinds of crazy songs. But We do Party and did I mention that is done during weekdays? Yup you will show up to your job drunk and without sleep and is the perfect excuse. At least that was the xmas I remember in my island. During the Season nothing was safe. And a lot of crazy songs.

I've always despised The Little Drummer Boy. It's just such a boring song!

'Jingle Bell Rock' and 'Grandma Got Run Over By a Reindeer' are pretty bad...but the one that really makes me envy Helen Keller her deafness is 'The Chipmunk Song (Christmas Don't Be Late)' with Alvin bitching because he wants a hula-hoop...HE DOESN'T EVEN HAVE HIPS!! I've always thought it was a bit creepy anyway, Dave Seville adopting three rodents as his children...

Silent Night. You’ve got a thirteen-year-old girl, giving birth, in a barn... and you’re gonna tell me it was a “silent night”?

But I also have a favorite Christmas song version: A Great Big World: I Want a Hippopotamus for Christmas.