When asked this question, I thought about it for the umpteenth time. I was asked if I felt "While You Were Sleeping" is a Christmas movie. The main plot is about the romantic and family relationships. It does take place at Christmas and they do celebrate Christmas but it's not the main plot. I feel there are multiple levels of Christmas movies. I would put "While You Were Sleeping" as a Number 3-Christmas-Adjacent level.
Number 1 is the purest form. It includes Santa and the main plot revolves around Christmas. An example would be "The Santa Clause". It's about a man becoming Santa and taking on that role for Christmas. This seems to be the lowest percentage of movies. So few, considering there's a good 1,000 Christmas movies out there. Another example is "Becoming Santa". Santa's daughter is dating a toy maker and brings him home for Christmas. Little does he know her parents are Santa and Mrs. Claus. He is surprised to learn that he has to qualify as the next Santa in order to be with her. Their relationship, and Jack Frost's attempts to sabotage it, is a subplot.
Number 2 is where Christmas is a leading plot line but it shares the story with the story of the people. An example would be "Eloise At Christmastime". Part of the movie is about the people that live at the Plaza with Eloise and her trying to get the manager's daughter connected with her friend, the manager's daughter's former love. The remainder of the movie is about Eloise and her Nanny preparing for Christmas. Decorating, shopping, music, making lists. Seeing how they celebrate is a good portion of the movie. Another example would be "Switched For Christmas". Two twin sisters switch places. One takes over planning the corporate Christmas party and the other takes over planning the Christmas carnival for the school her twin teaches at. The majority of the movie is planning Christmas events but the relationship of the twins and their budding romances take part of the spotlight.
Number 3 is sort of Christmas-adjacent. It takes place at Christmas and has tons of Christmas decorations, traditions, and music, but Christmas isn't a main part of the plot. It's more of a setting. An example would be "Christmas Connection". It takes place at Christmas and there's some celebrating but the primary story is about the romance between the flight attendant and the widowed father as well as her relationship with his daughter. It's also about the father helping her search for information about her deceased parents. Another is "A Season For Miracles". It even has an angel in it. It takes place at Christmas and there are decorations and a visit to see Santa but it's just a backdrop. The main story is about an aunt who is in hiding to keep her niece and nephew out of foster care. Through a case of mistaken identity, she is embraced by the town. Both of these have Christmas in them and foster the Christmas spirit but Christmas isn't the main point.
Number 4 is those that just happen to take place at Christmas but you could easily argue they aren't Christmas movies. There's no real Christmas in them. Just a drop or two. You could easily remove the little bit of Christmas and the movie would be the same. An example is "Die Hard". The fact that it takes place at Christmas is inconsequential to the story. Another example is "Gremlins". Remove Christmas, break the rules, and craziness still ensues. These are the movies that most people tend to argue about the most. Is it or isn't it a Christmas movie. I guess, if it takes place at Christmas, you can count it. This category is one I leave up to the individual. The one thing I'll say is if you argue over whether it's a Christmas movie or not, you're missing the point of Christmas.
I hope this helps you with how you think about Christmas movies. Before you know it we will have new 2020 Christmas movies.
Until we meet again....