I’ll let you in on a little family secret: my wife is one of those people. You know, the people who would listen to Christmas music all year round, set up the Christmas decorations in October and leave them up until March. In the interest of familial harmony, however, she restrains herself to celebrate Christmas between late November and early January. I won’t lie, I also love the so-called “Christmas Season.” I like the cold weather, bundling up and going to parties with friends, spending time with family, decorating the house and the various Advent and Carol services held at church.
For many people, myself included, Christmas is a time of deep nostalgia. Many of us have fond memories of Christmas as children. We relish old Christmas music/movies, our tattered old stockings, handmade Christmas-tree ornaments and a big Christmas feast shared with family. Oddly enough, these actual memories are supplemented by a sort of collective nostalgia as propagated in images of snowy cottages, warm fires (even though many these days did not grow up with fireplaces), church bells and many other stock images. At times our nostalgia overrides other ordinary judgments, like aesthetics. How else can we explain some of the horrendous songs or arrangements played at this time of year, beloved by all and counted as classics, which we would never be caught dead listening to in another context?
Strikingly, nostalgia can even occur in memories of terrible events, like the state of East Germany behind the Iron Curtain and the events of the cultural revolution in China. Collective nostalgia such as this (but also in less extreme cases) is a reaction against the fast-paced, complex, progress-oriented nature of daily life in which we long for a simpler time. This feeling results in a kind of distorted memory of our past (or some collective past) in which the good is emphasized and the difficult downplayed. 
At its root, nostalgia is intimately tied to memory and the types of stories we tell ourselves about who we are. It is here that my concern with nostalgia meets up with the concern of the many who rail against the commercialization of Christmas. I think the stories that we tell ourselves through our personal and cultural nostalgia tend, in practice, to override the story of what Christmas is actually about: the creator God divesting himself of glory and coming to earth in the person of Jesus as a baby to rescue us and reunite us with him. Telling this story and relating who we are to this story creates a very different atmosphere than one of telling fictionalized and commercialized stories from our collective past. This is not to say that decorations and beloved music are bad in themselves, but it is rather to encourage reflection on what is really the dominant story for our “Christmas Season.” We celebrate the person of Christ, not idealized Christmases of yesteryear. In the words of St. Augustine:
“Awake, mankind! For your sake God has become man. Awake, you who sleep, rise up from the dead, and Christ will enlighten you. I tell you again: for your sake, God became man…Let us then joyfully celebrate the coming of our salvation and redemption. Let us celebrate the festive day on which he who is the great and eternal day came from the great and endless day of eternity into our own short day of time.” 
 For a fascinating account of this, see Janelle L. Wilson’s Nostalgia: Sanctuary of Meaning (Rosemont Publishing, 2005), 21-29.
 St. Augustine, Sermon 185: PL 38, 997-999.