Humor is woven throughout “Why I Live at the P.O.,” and no character escapes Sister’s appraising, comically judgmental eye. Uncle Rondo wears a kimono, and Shirley-T., like her namesake Shirley Temple, sings and dances on cue. Stella-Rondo persists in absurdly claiming that Shirley-T. is adopted, and Papa-Daddy has a beard that he claims he’s been growing since he was fifteen. Sister herself is comical, hauling her belongings to the post office with the intention of living there. Even when she doesn’t necessarily intend to be funny, her overly earnest and dramatic rendering of Stella-Rondo’s return comes across as humorous. The relentlessness of Sister’s elaborate narration, in which even small happenings become absurd, momentous events, make the story a rather wild ride through a strange world where people seem to adhere to their own set of rules.
From the beginning, however, Sister is doing more than just poking fun at her family and surroundings, and Welty employs humor to call attention to unsettling truths about her characters’ lives, particularly Sister’s. Sister wants to give the impression that she is not deeply affected by the family’s infighting and tries to portray herself as a victim, free from any blame in the family’s disintegrating relationships. Her humorous tone is a means of deflecting unpleasant realities, a mask that she can hide behind to avoid showing her true feelings. The distance she deliberately places between herself and genuine emotions becomes more apparent as the story progresses, ultimately darkening the over-the-top humor and emphasizing Sister’s isolation.