In Chapter 26 of "To Kill a Mockingbird," Scout's question upsets Jem when Scout mentions Miss Gates's words as she came out of the courthouse, saying that
it's time somebody taught'em a lesson, they were gettin' way above themselves, an' the next thing they think they can do is marry us.
The hypocrisy of Miss Gates is a bitter reminder to Jem of the travesty of the trial of Tom Robinson, in which an innocent man was condemned because of his race and mere circumstantial evidence.
Jem states that he understands why Boo Radley "remains shut up in the house all this time": Boo "wants to stay inside." Much like Boo, Jem senses the cruelty and injustice of the world outside one's home, and he is greatly disturbed by his unanswerable question:
If there's just one kind of folks, why can't they get along with each other? If they're all alike, why do they go out of their way to despise each other?
The bias and pettiness of human nature is confusing and frustrating to the logical mind of Jem. For him, "the world is too much," and he suffers from the disappointments of reality and an answer that cannot be found in human nature.