Another irony of "Good Country People" comes in the title. Applied by Mrs. Hopewell, this phrase is used ironically and has several meanings. The phrase unites and identifies Mrs. Hopewell while also distinguishing her from more common people. Additionally, the fact that the phrase exists serves to aid Manley, who takes advantage of the cliched notions attached to the phrase.
He uses the phrase as a "cover" for his actual intentions, appearing to be a "good country person", allowing others to see him in this simple light, and surpising them unawares when he has manipulated them into position.
Another irony to this story of O'Connor's is that the artificial leg Hulga wears is what makes her a distinct individual; yet it is the very thing that undoes her individuality, thus rendering her just another vulnerable female that Manley Pointer dupes.
Flannery O'Connor has a great sense of humor--and this story is a perfect example. Ok, not in a "ha ha" sort of way, but still...
You have to remember that she was a Catholic who describes the south as "christ haunted". Her protagonist Joy/Hulga is a self proclaimed nihilist. She reads Nietzche and believes in 'nothing'. In this story Flannery O'Connor exposes Joy/Hulga and her pretentious education as being little more than a coating on top of Joy's upbringing. When it comes down to it. When she is in that hayloft and scared she confronts him with her mother (who she professes to loath)'s line about 'Good Country People' the irony lies in the fact that Manley Pointer is exactly what she professes to be...and the logical extension of those beliefs. And Joy is stripped of her belief system and left in that loft--begging the question, what do you do when 'nothing' has been taken away from you?
What a great story!