Why does the merchant claim to feel worse than he did before the boy arrived to work for him?

From the text:

"You have been a real blessing to me. Today, I understand something I didn't see before: every blessing ignored becomes a curse. I don't want anything else in life. But you are forcing me to look at wealth and at horizons I have never known. Now that I have seen them, and now that I see how immense my possibilities are, I'm going to feel worse than I did before you arrived. Because I know the things I should be able to accomplish, and I don't want to do so."