Mrs. Johnson says that Maggie looked at her sister (Dee) with "envy and awe."
She thinks her sister has held life always in the palm of one hand, that "no" is a word the world never learned to say to her.
Maggie is the one who is burned in the house fire. She is thin and, according to Mrs. Johnson, walks like a lame animal. Dee is described as "lighter" with nicer hair and a full figure. The implication is that Maggie simply had a more difficult time as a child and Dee, because of her determined personality and good looks, usually got what she wanted. And as much as Dee disliked the house and their living situation, she didn't hate her family. She simply wanted something different. This is why, after going to school, she would read to Maggie and her mother, giving them knowledge about other cultures, other ways of living, "other folks' habits." As the story unfolds, we learn that Dee is trying to get in touch with her African heritage but at the expense of ignoring her more immediate family heritage. So, there is the sense that prior to and after Dee left, she'd always loved her family but always wanted them to change (as she would) and become more "cultured."