The Literature: Balthazar, by Lawrence Durrell.
The Set-Up: One of the characters, Nessim, has returned from the city to his home to tell his brother Narouz and his mother that he is engaged. Although he's happy to see his brother, he's repulsed by Narouz's harelip. Narouz himself is repulsed by it, and refuses to visit the city out of shame. The narrator goes to some effort to make sure we are repulsed by it as well.
The Weird Moment: "He [Narouz] was still swollen up toad-like by the laughter, though his expression had now become serious. 'My god,' she [his mother] thought, 'how ugly he is.'"