What is a short summary of the story, I'm Working on My Charm, from the collection, Trash: Stories?

In the story, I'm Working on My Charm, the narrator is at a cocktail party in the North where a woman treats her differently because the narrator is a Southerner. This experience in her adult life reminds the narrator of when she was a teen and worked in a diner with her mother. While the waitresses could predict how Southerners would tip, they never knew what Northerners – like the woman at the cocktail party – would do. The narrator knows she needs to play into Southern stereotypes to get ahead.