IMHO, there are really two holidays called "Christmas" at this time of the year.
One is the secular bacchanalia. "Buy buy buy!" is it's theme. Greed and avarice are it's purpose. It knows of no religion... it doesn't care if you're Christian, Jewish, Muslim, Buddhist, Wiccan, Atheist, Agnostic, or if you worship by rubbing blue river mud in your navel. You are to be manipulated and guilted into buying. Spend and spend more.
This "holiday" I despise.
The other, however, is the truly religious holiday. For those who Believe, who honestly have Faith in a Christian God and all the related trappings, it is a time of good will, family, friends, and a chance to Celebrate their Faith. Those who Believe but are not of a Christian flavor often have a similar religious holiday about the same time, and it is used for the same purpose. (I don't know what those who don't Believe have as a substitute, maybe just a hope for a joyous New Year by the calendar, but if there is something appropriate, insert here).
This is the holiday I choose to celebrate. Granted, with my wife's family it is as an outsider looking in, but I participate in the positive aspects of this with them, just omitting for obvious reasons the religious aspects.
Now my wife, she gets caught up in both. I think she gets a little overboard when it comes to spending $$ on the kids, nieces, nephews, and grandkids. Most of them aren't yet aware of the secular monster, even as they benefit from it. They still live in a world where the religious holiday is the only one. But they are yet young.