What does Gulliver find most disheartening about society upon returning home?

Upon returning home, Gulliver finds the prevalence of selfishness and corruption in society to be the most disheartening aspect. This reflects his disillusionment with human nature, which has been a central theme throughout his travels. Having experienced the various civilizations in Lilliput, Brobdingnag, Laputa, and the Houyhnhnms, he gains a broader perspective on how people often prioritize their own interests over the common good. In contrast to the Houyhnhnms, who embody rationality and virtue, the moral decay he observes in his own society strikes him as particularly disheartening. This realization underscores the critique of human flaws and societal shortcomings that Jonathan Swift conveys through Gulliver’s experiences and transformations as a character. It highlights the stark contrast between the societies he visited and his own, leading to a profound sense of disappointment.