People who lost someone, people who are separated from their loved ones, people who are introvert but must act sociable, people who are depressed but must act chipper or else be asked questions, people who are alone but see all other people getting together for parties, people that hate their families but cannot escape the obligatory gathering, people who are poor but feel pressure to give gifts and have a lavish meal.

The list is endless.

> edit 2: Got it, no questions allowed.

Please don't add bits like that to HN comments. They're off topic and break the guidelines and will lead to further downvotes.

Re your question, there's lots of discussion out there:

https://www.google.com/search?q=holiday+depression

If you're depressed or something very bad's happened in your life, the contrast of it being a time of celebration and seeing everyone else happy can be especially painful. Kind of like being forced to go to a jubilant party where everyone's singing and dancing the day after your best friend died, for example.