I have been a solipsist all my life. A solipsist, in case you don't happen to know the word, is one who believes that he himself is the only thing that really exists, that other people and the universe in general exist only in his imagination, and that if he quit imagining them, they would cease to exist.
One day, unintentionally, I became a practicing solipsist. Within a week, my wife had run away with another man, I lost my job as a shipping clerk and I broke his leg chasing a black cat to keep it from crossing my path.
I decided, in a hospital, to end it all.