A symbol in “Why I Live at the P.O. is Shirley-T, Stella-Rondo’s daughter. She is a symbol both of the life the narrator could have had and how her sister took it from her.
Much of the tension in the family gathering is caused by Shirley-T. Stella-Rondo has just left her husband, Mr. Whitaker. The narrator is jealous because Mr. Whitaker was “the only man ever dropped down in China Grove” and her sister got him “unfairly” and then came home “giving no rhyme nor reason whatsoever” for why she left and “no explanation for the presence” of Shirley-T.
Shirley-T is clearly too old to have been born during Stella-Rondo’s short marriage to Mr. Whitaker. She also looks like Papa-daddy, their grandfather. Yet Stella-Rondo insists she is adopted and the rest of the family is ready to accept the fiction. The narrator is the only one who does not, because she sees Shirley-T as a symbol of the life Stella-Rondo stole.
And if Stella-Rondo should come to me this minute, on bended knees, and attempt to explain the incidents of her life with Mr. Whitaker, I'd simply put my fingers in both my ears and refuse to listen.
The narrator blames Stella-Rondo for stealing her boyfriend, for lying about it, for having a child with him out of wedlock, and for leaving him. She refuses to accept what really happened, or to peacefully believe the lie either. Instead, she keeps pushing, causing her sister to push back and alienate other family members against her.