i think what some people don't understand about "holiday cheer" is that it's hard for everyone in winter. there's not some secret class of people for whom holiday cheer comes naturally. i mean, i guess there might be people who have summer SAD, but thats not the point.
throughout human history where these midwinter celebrations originate fromn, they serve a sociological purpose that keeps them cropping up across cultures; keep morale up through the hardest season of the year. people starve. people get sick and die in close quarters. to celebrate is an act of defiance against a world that wants you to pass quietly into the long, cold nights.
under capitalism there's also the end of a fiscal year. Q4 layoffs are common. a lot of people are either getting fired or going through some of the busiest and most hectic times of year at their jobs.
there's also, on the gregorian calendar, the emotional weight of the end of a year. it's reflective. we remember people we have lost, old wounds open. to reduce this to Seasonal Affective Disorder in particular leaves a bad taste in my mouth because i think it pathologizes a universally human experience. and grief is universally human. and the older you get the more universal it is.
i don't know. i know it's hard. everyone's going through something in the winter. just try not to disparage people, especially strangers, who you feel like are Trying Too Hard at the holiday cheer thing. i know if you're going through a seasonal-affective depression -- or, shit, situational hardship -- it can be really grating, like cinnamon in your mouth. but everyone's coping with something, and some people do that best by embracing traditional celebrations. humans are pretty good at that.