Quote.
ANTONIO
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, The Merchant of Venice