Before Dee arrives, Mama describes Maggie as being like "a lame animal, perhaps a dog run over by some careless person rich enough to own a car, [who] sidle[s] up to someone who is ignorant enough to be kind to him[.] That is the way [...] Maggie walks." Maggie has little confidence, is painfully shy, and, to Mama, she seems beaten down and kind of sad. Such a comparison, to a lame dog who's been hit by a car and is desperate for kindness, is quite telling because it makes Maggie seem a little pathetic. Maggie doesn't ask for much, or anything at all really, and she lives a quiet existence with her mother. Maggie wants to blend in, to hide; she even tries to hide as Dee's car pulls in.
Dee, on the other hand,
"wanted nice things. A yellow organdy dress to wear to her graduation from high school; black pumps to match a green suit she'd made from an old suit somebody gave me. She was determined to stare down any disaster in her efforts. Her eyelids would not flicker for minutes at a time. Often [Mama] fought off the temptation to shake her. At sixteen she had a style of her own: and knew what style was."
Dee is self-assured, even arrogant. Mama raised money to send Dee away to school, and Dee seems to have been embarrassed by her upbringing and home since then. Even as a child, she wanted more and better. She wants to be seen, to stand out; she wears a dress that has "yellows and oranges enough to throw back the light of the sun" because, unlike Maggie, Dee wants to be visible, to be the center of attention.
Mama, the narrator of the story, gives quite contrasting descriptions of her two daughters, Dee the elder, who has moved out, and Maggie, who still lives with her. As she waits for Dee to come and pay them a visit, she describes Maggie as being quiet, shy and awkward while remembering Dee as being quite a different type, brash and bold, always wanting things for herself. Dee also had the chance for a proper education unlike Maggie, and Mama. When Dee actually arrives, this contrast is confirmed; Dee is still talkative and self-assured while Maggie seems to become even more withdrawn in her sister's presence.