I just grew up watching a lot of movies. I'm attracted to this genre and that genre this type of story and that type of story. As I watch movies I make some version of it in my head that isn't quite what I'm seeing - taking the things I like and mixing them with stuff I've never seen before.
The truth is that our way of celebrating the Christmas season does spring from myriad cultures and sources from St. Nicholas to Coca-Cola advertising campaigns.