“The minds of men always dwell more on bad luck. They accept ordinary prosperity as a matter of course. Misfortunes arrest their attention and remain in their memory.” William Graham Sumner, Folkways A Study of the Sociological Importance of Usages, Manners, Customs, Mores, and Morals (1906).
That 100-year-old observation has been borne out by modern science. Winifred Gallagher explored the strength of negative thoughts in her excellent Rapt, Attention and the Focused Life. Unpleasant thoughts and feelings like sadness, fear, and anger occupy our attention more than pleasant thoughts for the simple reason that the negative ones are more powerful. It’s a natural inclination and one we need to struggle against, just like we struggle against natural inclinations in many areas of our existence.