Everything That Rises Must Converge

I thought that O'Conner's "Everything That Rises Must Converge" was sad, but realistic in older times.  Julian treated his mother poorly, and even though she was wrong in her beliefs, she didn't deserve to be treated so poorly by her son.   The end of the story confused me however, it seemed as if a piece of the story was missing. I also thought that it was ironic that he was the one supposedly teaching his mother a lesson, when in fact Julian was the one who learned the lesson in the end.