The man who feels himself all-perfect, naturally enough despises all further improvement. His self-sufficiency and absurd conceit of his own superiority, commonly attend him from his youth to his most advanced age
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“that he was not a lover of danger, or forward to expose himself to little dangers, but to great dangers; and that, when he exposed himself to danger, he was altogether regardless of his life.17 The proud man is commonly too well contented with himself to think that his character requires any amendment. The man who feels himself all-perfect, naturally enough despises all further improvement. His self-sufficiency and absurd conceit of his own superiority, commonly attend him from his youth to his most advanced age; and he dies, as Hamlet says, with all his sins upon his head, unanointed, unanealed.18 It is frequently quite otherwise with the vain man. The desire of the esteem and admiration of other people, when for qualities and talents which are the natural and proper objects of esteem and admiration, is the real love of true glory;” source