Gulliver travels to strange lands and eventually develops a deep respect for the Houyhnhnms, advocating for the extermination of all humans (only to discover that he is a human and will therefore have to leave); when he returns home, he is disgusted by his wife and children.
Genly Ai travels to Gethen and learns about their very different ways (making assumption after assumption and having to set them aside as he learns more). When he returns home, he is horrified by those of his own species but also repelled by the Gethens.