Besides this, there are other causes which at times erase the greatest services from our minds. The first and most powerful of these is that, being always intent upon new objects of desire, we think, not of what we have, but of what we are striving to obtain. Those whose mind is fixed entirely upon what they hope to gain, regard with contempt all that is their own already. It follows that since men’s eagerness for something new makes them undervalue whatever they have received, they do not esteem those from whom they have received it. As long as we are satisfied with the position we have gained, we love our benefactor, we look up to him, and declare that we owe our position entirely to him; then we begin to entertain other aspirations, and hurry forward to attain them after the manner of human beings, who when they have gained much always covet more; straightaway all that we used to regard as benefits slip from our memory, and we no longer consider the advantages which we enjoy over others, but only the insolent prosperity of those who have outstripped us. Now no one can at the same time be both jealous and grateful, because those who are jealous are querulous and sad, while the grateful are joyous.