500
“In my younger and more vulnerable years my father gave me some advice that I've been turning over in my mind ever since. "Whenever you feel like criticizing any one," he told me, "just remember that all the people in this world haven't had the advantages that you've had."
How does this quote set the tone for the rest of the book?
It establishes Nick as thoughtful, privileged and judgmental (when we find out that he is actually judgemental; him saying that at the beginning puts an emphasis on it). Nick wants to encourage us to trust his judgment.