Why are cloudy days so annoying?

The main reason is the lack of sunshine. Not only is the weather bad on cloudy days, there is a kind of seasonal depression in psychology, which means that some people will suffer from depression in winter when the days are shorter. , but once the spring comes, the depression will not be cured, but it will relapse in the next winter. So it is sunlight that affects people's mood chemically and psychologically.

This is why the suicide rate in winter without sunshine is much higher than in summer with plenty of sunshine