Most people typically blame others or their situation for the way they feel. Seasonal Affective Disorder is apparently a real thing, but I don't buy into it because I have Generalized Anxiety Disorder across the board. The difference though, is that I am keenly aware of it. I didn't get diagnosed until I was over 45 years old.
People who are not aware of, or diligent about their own mental states are highly susceptible to cognitive biases and certain logical fallacies, beginning with the Fundamental Attribution Error or Attribution bias, or Misattribution of Arousal. (Arousal in the sense of something getting one's attention, not sexual.)
We are all guilty of saying someone or something makes us angry, or the weather makes us sad, or we allow ourselves to feel loneliness in the absence of loved ones. The key is that we allow ourselves to feel mental anguish. Our brains only receive sensory input, what we do with it is up to us.