T.h. White said this quote

Finally, there was the impediment of his nature. In the secret parts of his peculiar brain, those unhappy and inextricable tangles which he felt at the roots, the boy was disabled by something which we cannot explain. He could not have explained either, and for us it is all too long ago. He loved Arthur and he loved Guenever and he hated himself. The best knight of the world: everybody envied the self-esteem which must surely be his. But Lancelot never believed he was good or nice. Under the grotesque, magnificent shell with a face like Quasimodo’s, there was shame and self-loathing which had been planted there when he was tiny, by something which it is now too late to trace. It is so fatally easy to make young children believe that they are horrible.