Book 2.26

We must now consider what is the main cause of ingratitude. It is caused by excessive self-esteem, by that fault innate in all mortals, of taking a partial view of ourselves and our own acts, by greed, or by jealousy.

Let us begin with the first of these. Every one is prejudiced in his own favour, from which it follows that he believes himself to have earned all that he receives, regards it as payment for his services, and does not think that he has been appraised at a valuation sufficiently near his own. "He has given me this," says he, "but how late, after how much toil? how much more might I have earned if I had attached myself to So and so, or to So and so? I did not expect this; I have been treated like one of the herd; did he really think that I only deserved so little? why, it would have been less insulting to have passed me over altogether."