What matters most are not things but relationships. At Christmas, we eat good food, have parties, and exchange presents. However, the relationships are what matter most as we do all these things. And as we remember the "reason for the season," namely the birth of Jesus Christ, we must remember that even this birth was all about relationship. Christ, the saving Son of God, left His place in heaven to be born as a man in order to have a relationship with us and provide an eternal relationship with His Father.
If we don't get past the manger and the birthday celebration of baby Jesus, we miss the significance of Christmas. For the real significance of Christmas is what happens approximately 37 years after the manger. It's what happens at the cross that gives us the real significance of Christmas. It is here, at the cross, that our broken relationship with God through sin is restored and forgiveness of sin is offered. Three days after the cross, we see that the power of sin is truly broken and through Christ's death and resurrection we can be reunited in a full, eternal relationship with God.
Not discounting the birth and perfect life of Jesus as part of the Gospel, but the real significance of Christmas is what occurs at Easter. Easter is why Jesus was born, namely to offer a once-and-for-all sacrifice for sin to redeem and reconcile us back into a relationship with God the Father, through Christ the Son. Easter is why we give gifts, namely because we have been given the greatest gift of all. Not just the gift of the Son of God born in a manger, but the Son of God who took on the penalty of our sin which we should bear and offers His righteousness to us which we do not deserve to bear.
In summary, the "reason for the season" is not simply a baby, King Jesus in a lowly manger coming to earth as a lowly servant. It is the Man, Lord Jesus lifted up on a cross rising to heaven as a warrior King.
Luke 2:10-11 “Do not be afraid. I bring you good news that will cause great joy for all the people. Today in the town of David a Savior has been born to you; he is the Messiah, the Lord”