As the grandmother rides with her ungrateful son, his disrespectful children, and his characterless wife on their way to a vacation in Florida, she describes an old plantation house she had once visited as a young woman.  She really wants to see it again, and so she invents a little story about the house having a secret panel behind which the original family's entire stock of silver is hidden.  It works, and the children beg their father to take them to see this mansion so that they can search for the long-forgotten treasure.  After a great deal of coaxing, an irritated Bailey agrees to take the family to see the plantation house, but as they traveled farther and farther down the road, the grandmother began to grow concerned, and the "horrible thought came to her."  It was "so embarrassing" that it caused her to physically jump, upsetting her cat, and causing the family's car accident.  The thought she'd had was that the house "was not in Georgia but in Tennessee."  Thus, she'd been leading her family down a dirt road for miles for absolutely no reason, and she knew this would anger her son greatly, and this is what prompted her reaction to this awful realization.