We expect cheer. We have parties. We put up ornaments and bright lights. We sing “Joy to the World” and “Hark! The Herald Angels Sing.” Not just in church, but in our homes. We even wander the streets at night singing to our neighbors.

We get and give more gifts in a 48-hour period than we give, or get, for the rest of the year. We even nab a couple of extra federal holidays.

And yet, Christmas makes a lot of us sad.

Why So Many Sad Songs?

Why are there so many melancholy songs about Christmas? Google “sad Christmas songs” and you get pages of articles, listicles and play lists. Not just sacred songs. From pop culture, we have dozens of gloomy Christmas tunes. There’s “Blue Christmas,” “I’ll Be Home for Christmas,” and at least five popular titles with the word “lonely” in it.

My favorite is Wintersong, from Sarah McLachlan. It’s about memories of a lost loved one.

I listen to this song every year! What’s going on?

I can think of two bad reasons and two good reasons so many of us feel sadness at Christmas.

Missing You

Let’s start with one of the good reasons. Friends and family gather at Christmas. We should think of loved ones who aren’t with us. If you’re alone, the whole culture conspires to remind you that your loved ones are somewhere else. It’s good and natural to feel sad, as long as you don’t wallow in it.

Unrealistic Expectations

Barbara Lilley points to the first bad reason for Christmas sadness: “We raise our expectations so high that we come crashing to the ground when things don’t turn out the way we had hoped.”

We picture a perfect Christmas even though we’ve never really experienced one. We assume everyday problems will take some time off. We want the tree lights to stay lit, the turkey to be moist, the church choir to nail the Hallelujah Chorus, the snow to be fluffy, and all our sane family members to be present, perky and accounted for.

And that never happens. Not all these things at once. The dog may poop under the Christmas tree. The kids may act like spoiled brats who need a tour of North Korea. Your crazy drunken uncle may show up. The middle section of the tree may go dark on Christmas Eve. Something irritating will happen. Count on it.

“In short,” Lilley explains, “a lot of people remember Christmas as every Christmas movie and television special they have ever seen.” Compared to a heavenly or even Hallmark ideal, any real Christmas is bound to disappoint.

To counteract this, focus on the good, and forget the minor irritants. I know. Easier said than done. But if you don’t want to feel the letdown, don’t expect the ideal.

The Self Gets in the Way

The second lame source of sadness? We focus on what we hope to get. The gifts, of course. But the other pleasures, too.

“Jesus is the reason for the season” may be a cliché, but it’s also true. Christmas is about God’s gift of Himself to us. It’s about a gift we’ve already received. Whatever portion of joy we feel, it will come when we focus on and imitate in small ways what God has done for us.

Whatever you do, try not to get used to the fact that the Creator entered the universe as a little baby.

We should find ways to shock ourselves about the truth of Christmas. Maybe it’s a long fast, or cold baths, or a midnight Mass, or a visit to a soup kitchen. Take up a prayer or other spiritual practice every day during Advent and Christmas, until January 5th. Whatever you do, try not to get used to the fact that the Creator entered the universe as a little baby. C’mon, he was born in a barn in a little village!

Light in Darkness

What’s the other good reason? It’s the best reason. We find it in the opening lines of John’s gospel. Read this out loud as if for the first time:

In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God; all things were made through him, and without him was not anything made that was made. In him was life, and the life was the light of men. The light shines in the darkness, and the darkness has not overcome it. …

He was in the world, and the world was made through him, yet the world knew him not. He came to his own home, and his own people received him not.

In the economy of God’s salvation, Christmas is D-Day, when the Allies stormed the beaches of Normandy. It’s not Victory in Europe Day, when the Allies won. It’s not the end. It’s the beginning of the end.

Try to see Christmas from the point of view of Mary and Joseph. Forget “Mary Did You Know?”. They knew. Before Jesus was even born, angels told them that he — the Son of God — would be born to “save his people from their sins.” They might not have grasped the details, but Mary and Joseph knew enough.

And we know. Christmas led directly to Good Friday and Jesus’s horrible death on the Cross. The journey that began in Bethlehem ended on Golgotha.

And God knew. The Son knew when he became man that he would die a painful death.

We shouldn’t think of that cuddly baby without also thinking of him suffering for us, for the sin we’ve brought into the world. Hatred. Murder. Greed. Lust. Self-absorption. On and on it goes. At Christmas, we celebrate the moment when all that horror began to be undone. But the horror is all too real.

That’s why Christmas should be neither bitter nor sweet. It should be bittersweet. Even ditzy pop singers seem to get the point.

To return to John’s image, Christmas is about light piercing the darkness. Our darkness. Expect some darkness, which casts in relief the brightness of the light.

Jay Richards is the Executive Editor of The Stream and Assistant Research Professor at the Busch School of Business and Economics at the Catholic University of America. Follow him on Twitter.