Jesus said to worship God in spirit and truth...
"Nevertheless, the hour is coming, and it is now, when the true worshipers will worship the Father with spirit and truth, for, indeed, the Father is looking for suchlike ones to worship him. God is a Spirit, and those worshiping him must worship with spirit and truth.” ~John 4:23,24 (see also: http://www.dnkjb.net/1189chapters/NT43JHN04.htm)
Since the celebration of "Christmas" is not based on truth, that is why I don't celebrate it...even though I'm Christian. You can make your choices, but I can't do something or believe in something that I know is not true.
The Catholic Encyclopedia says:
It is good to be with family and give gifts any time of the year. Why do it all at once, when society says we have to? It puts pressure on everyone and makes people hate being generous.