One thing that "A Good Man Is Hard to Find" and "Good Country People" have in common is the theme of innocence versus corruption. Both share this notion of "good country people," a kind of myth about how living the simple life on the farm can cause people to have a kind of natural goodness. In "A Good Man Is Hard to Find," the grandmother tells Red Sammy that "people are not nice like they used to be," a general lament for the loss of common sense and decency. Later, she tells the Misfit that she can tell he "comes from nice people," as if to say although he is a wanted murderer, she can see through to his natural goodness.
Of course, the Misfit is not a good person. In the same way, the Bible salesman in "Good Country People" is praised by Mrs. Freeman as "the salt of the earth," but in fact he is an opportunist who steals Hulga's artificial leg on a lark. O'Connor's mistrust of common sense finds a voice in Hulga, who has a PhD in philosophy and is an atheist, yet these views do not prevent Hulga from being victimized. In a way, the Bible salesman is just as educated as Hulga; he tells her, "You ain't so smart. I've been believing in nothing ever since I was born."
In both stories, the protagonists are victimized as much by their assumptions about the goodness of others as by the people themselves.