Both the Lilliputians and Brobdingnagians ultimately think poorly of Gulliver and his society.  The Lilliputians accuse Gulliver of treason because he peed on the palace (to put out the fire there), he wouldn't demolish Blefuscu (Lilliput's enemy), he did "aid, abet, comfort, and divert" the Blefuscudian ambassadors, and he only received verbal permission to visit Blefuscu from the Emperor of Lilliput and they believe that he will aid the Emperor of Blefuscu on this visit.  They desire to put him to "the most painful and ignominious Death."  

In Brobdingnag, after Gulliver explains his home and its customs to the king, the King says, "'I cannot but conclude the Bulk of your Natives, to be the most pernicious Race of little odious Vermin that Nature ever suffered to crawl upon the Surface of the Earth.'"  Once he learns of the warlike tendencies and the savage behaviors of the English, the king feels that Gulliver and his countrymen are lower than rats or roaches.  While the Lilliputians would hardly describe Gulliver, a giant to them, in this way, their behavior and his conviction of treason indicates the extent to which they have a problem with him and his customs.