People tend to be more unhappy during the holidays than other times of the year. Holidays are the times when people have to put on a fake presentation of who they are and how their lives are going, for the sake of impressing their family members whom are only seen during the holidays. This causes huge stress levels, and people become unhappy because of it. For unknown reasons, they look fondly on the memories of these events, and block the stress out.
The holidays are supposed to be a season of joy and cheer. So why does everyone look so angry? Why are suicide rates exponentially increased during the holidays? Why are emergency rooms so busy during this time? Because the holidays are for children and corporations. Children get to enjoy all the toys and food without any of the work required to produce any of it. You get to meet new people and family for the first time. Its exciting as a child. As an adult, there's things to buy, deadlines to meet, traveling plans to maintain, relatives to deal with, and kids on a three month sugar high that starts at Halloween and doesn't end until mid January.
During the holidays people are more stressed to get things done and get them done right. During certain holidays people want to give their kids all the cool and awesome presents they can to make their kids happy. This puts to much stress on people and parents just to struggle to get some gifts.
Holiday's use to be a time where families would get together and enjoy each others company. Not anymore. It seems that the pressure of new toys and spoiled children have made the holiday's more stressful than actual fun. Holiday's also seem to bring out negative memories in people. Whether you lost a loved one or received a gift you didn't feel was adequate. There are more suicides or attempted suicide over the holidays than any other random day of the year. Why? As I mentioned earlier. The pressure or stress that has been placed on these days to be so huge or successful.
I do think that more and more people tend to be unhappy during the holidays. I think a lot of that has to do with the fact that the holidays in Western countries have shifted the focus to a more commercial and consumer based way of celebrating rather than one based on the spirit of the times.