"In sooth, I know not what makes me 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."
The Merchant of Venice Act I Scene I lines 1 to 5
It was the first Shakespearean play that I ever studied, and for some reason, these words just stuck with me.