Family conflict lies at the heart of “Why I Live at the P.O.” The story explores the relationship dynamics among multiple generations living together in the same house, which more often leads to isolation than “togetherness.” While Welty highlights the rivalry between the narrator and her younger sister, the story illustrates the ways that the family’s overall dynamic perpetuates this rivalry.

The names of all the characters (apart from Stella-Rondo) include their familial relationship with the main character—known only as Sister—which serves to further Sister’s view of Stella-Rondo as an outsider. Sister emphasizes that the family was doing just fine until she returns: “I was getting along fine with Mama, Papa-Daddy and Uncle Rondo until my sister Stella-Rondo just separated from her husband and came back home again” (43). While the story’s conflict is driven by the sisters’ respective relationships with Mr. Whitaker, Sister points out that their dynamic goes back further. Sister describes Stella-Rondo is described as “spoiled” because Stella-Rondo is exactly 12 months younger, for instance, and shares an example of Stella-Rondo losing a necklace Papa-Daddy gave her. The narrator thus establishes that her jealousy has deep roots.