We do not have to visit a madhouse to find disordered minds; our planet is the mental institution of the universe.

Goethe

In sooth, I know not why I am so sad.

It wearies me; you say it wearies you.

But how I caught it, found it, or came by it,

What stuff 'tis made of, whereof it is born,

I am to learn.

And such a want-wit sadness makes of me,

That I have much ado to know myself.

William Shakespeare