I finished Gulliver’s Travels, it got very harsh at the end. Gulliver’s last voyage is to the land of the Houyhnhnms, intelligent horses that live in an ideally rational society. The humans are Yahoos – filthy, deformed, stinking savages (Swift spends a while describing the long hairs that grow around their anuses, and at one point they poop on Gulliver’s head) that the horses use as labor. Gulliver spends several years serving a noble Houyhnhnm, coming to admire them.  When Gulliver gets back to England (on a boat with a sail made of Yahoo skin!), he’s been so twisted by his experience that he finds all humanity loathsome (he finds it disgusting to touch his children or share a drinking glass with his wife,) and spends his days hanging out in a stable. Jonathan Swift did end up going insane later in life.

For some reason, they never get past Lilliput in the cartoon versions I’ve seen.