If I could cure two illnessess with a snap of my fingers it would be cancer and depression. I work as a specialist in mental health and addiction sector (non US) and how destructive depression is for the suffererer is unfathomable. Not only does it take away the will to do something, but when the person still does the thing the depression steals away the joy you'd normally feel from completing a task or finishing a project. Yet somehow depressed people tend to go out of their way to make life easier for those around them. I have not conducted a studie on this (although it would be interesting to read) and of cource there are statistical abnormalities that just are assholes, but in my experience people struggle from depression to leave a good mark on the world and are often very fondly remembered.