For many people (and too many IMO) - it's a very depressing time. Suicide rates are high. Plus it's been driven into our heads (Joseph Goebbells style) that everyone has a loving family and close frieds galore. Not so. In the real world.
I don't "celebrate?" it for whatever the invented religious reason/s. But it's kinda nice seeing people being a bit nicer for awhile. I like the lights, decorations and being from the Northeast I like the snow for the Holy-Daze. But the same old music is a tad annoying. The commercialism, shopping stuff, buying and exchanging gifts is kinda fake and automatic/expected in most cases too. And what specific gifts makes people "happy" is often overly expensive as parents and people are expected to pay an arm and a leg to "show their love." Odd values seem to surround true happiness these days.
As a chiropractor, I often talked with many of my clients and found out just how may people absolutely dreaded he holidays (the cooking, fighting the traffic to shop, seeing idiot relatives they hate, traveling, etc) It was a shitload.
Parents seem to love it for their kids but then again kids are up for any type of party where sweets and gifts are handed out freely then throw in some flashing lights and cartoon characters. I never understood the "sitting on Santa's lap" stuff. It always seemed a bit strange to me. And I still question lying to children about the Santa thing and how that effects the trust relationship between parents and the child.
But overall I say happy holidays (the PC term) to anyone I see at that time and find it kinda' nice. Although I do cringe at the guys and gals that have to wear the Santa cap everywhere they go and do it every year. But hey, it makes them happy.
OTOH I do find some true and meaningful celebration for the Winter Solstice. That's something I can really bite into.