One of the things that makes the ending of Bobbie Ann Mason's story "Shiloh" so arresting and memorable is its ambiguity, in that the meaning of the last sentence isn't clear and is subject to interpretation. Are Leroy and Norma Jean doomed, or do they have a second chance at happiness? Like the cliched "glass half full or empty" personality types, the reader's takeaway from Mason's realist finale depends largely on whether one is an optimist or pessimist about human nature and relationships.
Mason supplies the reader enough facts and details about the individuals and their troubled relationship to suggest that Leroy constantly misunderstands his wife and her emotional needs and that his fecklessness has finally gotten to be enough for the evolving Norma Jean, who is intent on continuous self-improvement. His confusion in that last scene is not knowing whether she is "beckoning" him towards her—and possibly towards a better future—or doing her familiar arm exercises in a display of vigorous, self-possessed freedom and rejecting him. As someone who consistently reveals a lack of empathy, responsibility, and practicality, Leroy is not a particularly sympathetic character and is clearly existing on a different emotional plane than Norma Jean. By the end of the story, it's plain to the reader that the two have very little in common and that Leroy doesn't offer much appeal anymore. Either way, it seems clear that Leroy is about to experience a significant change, as is made clear by the "too pale" color of the sky he is approaching, which reminds him of the dust-ruffle given to the couple by Leroy's mother-in-law, who didn't like Leroy. This could be a hint that the story ends on a hopeless note.
Then again, while Norma Jean does announce that she wants to leave and believes the marriage to be over and the best behind them, she also lacks confidence in herself and immediately second guesses her decision. Since Mabel blames Norma Jean for her baby's death and has traumatized Norma Jean with her callousness, Mabel and her dust ruffle suggest the oppressiveness of the characters' lives and the pain of historical memory, accentuating Leroy's dread and foreboding.