You know the songs of Christmas; you’ve sung them every year since you were a kid. But did you know where they came from and how old they are? The Christmas carol “Hark! The Herald Angels Sing” was sung for 100 years before it got the tune we are familiar with. “Deck the Halls” was a New Year drinking song that received cleaned-up lyrics. And that legend about “Silent Night”? Not a true story. One origin story that tickled me was who wrote “All I Want For Christmas Is My Two Front Teeth.” It was an elementary school music teacher.
In 1944, grade school teacher Donald Yetter Gardner and his wife Doris sat down with a group of second-graders in Smithtown, New York, to help them compose a song for Christmas. While there are different versions of the origin, they all involve a bunch of children saying, "All I want for Christmas is…" It's not so much that any students wished for those absent front teeth, but more that Gardner was charmed by their requests hindered by toothless lisping.
There’s more to the story, of course, and quite a few others, in a list of Christmas song origins at mental_floss. With videos.