I don't hate Christmas for the usual reasons. There's plenty that's wrong about Christmas, for sure. Christians stole the Winter Solstice holiday, which sucks. I'll bet a pagan holiday, celebrating fertility and stuff, and doing dances in the sunrise to encourage the sun to come back up in the sky, would be a lot more interesting than worshipping a little baby whose mother didn't even have sex first. Besides which, Jesus as we know him probably didn't actually exist. But that's another story.
No, the reason I hate Christmas is the same as the reason I hate weddings. The best thing you can hope for at a wedding or at Christmas is to just barely meet expectations. And 90% of the time, you won't, and someone will be pissed off about something.
I actually like the Christmas "spirit" sentiment, of gathering with family, sharing, forgiving ... that's really good stuff. Christians didn't invent it, but they've really developed it into something extravagant.
But expectations are too high. We expect a joyous time, where everyone gathers in peace and harmony, Santa brings exactly what the kids wanted, dinner is perfect, you get Christmas cards from all the relatives and friends you care about and none from the folks you'd rather forget, and there's just enough snow to be pretty but not enough to get stuck.
With expectations like that, you're lucky if you barely make it, and nobody is pissed off. But chances are, one or more expectations won't be met, and someone will be disappointed. Maybe Uncle George and Aunt Georgine are late and dinner is a little cold, or Johnny gets the wrong Lego set, or cousins Geraldine and Maybelle renew that fight they started last Christmas.
So now I boycott Christmas. I have no expectations, because to me, Christmas is just another day. I tell my kids and family that it would be wonderful to get together at the end of the year some time, just to celebrate the year gone by and look toward the new year. But we do it one a day when it's convenient for everyone, and we have a nice simple dinner. We get out our instruments and play a few songs, play charades or fictionary, and have a great time. We have no big expectations, and every year, we manage to exceed those expectations and go home happy.