Darkness
It won't be long before the days start getting longer. When I was younger this time of year would get me down, due to the lack of light. Especially being in school, going in in the morning in darkness, and then leaving in darkness (after swim practice). Of course the holidays helped, with the lights and festivities.
Interestingly, I look at it differently now. I like the snow (when it's not a disastrous amount that causes all sorts of havoc), and I like the change of seasons. Moving to the workforce, where your life isn't defined by the school year does that.
Still, I'll appreciate it when the days start getting longer. But sometimes darkness is nice too.
Find me at @toroidalcore@hackers.town