What and why do I celebrate Christmas?

I'm teaching tonight at SPIN (our High school environment) in preparing for this week I asked myself this question. And if I'm honest the answers really don't have a lot to do with Jesus, at least in as far at the traditions go.

Don't get me wrong I definitely reflect on the fact that God became human. Chose to dwell among us, so that the world could be in a relationship with him.  That's just plain crazy by the way when you really think about it:

GOD became an infant, Grew up to be a sinless man, Died a bloody awful death, so that we could  have a relationship with him.

I could make a good case that really we celebrate this through out the year as followers of Christ. 

But what do christmas trees, gifts, shopping, hot coco, christmas movies, christmas songs have to do with an infant, that came to redeem humanity?  I'm still not sure exactly I think a lot of it has to do with family, and friends. 

I'm not saying it's bad or wrong, I'm just thinking through how it all connects and why I enjoy the season so much, and really what am I celebrating? 

I'll let you know if/when I decide on something.