Loma and Mary Willis are quite different in most aspects of their personalities. Physically Mary Willis is said to be plain like her mother, whereas Loma is fancy "even at home." Mary Willis is responsible, polite, and concerned with how she and her family appear to others. Loma is immature, dramatic, spoiled, jealous, and often mean. She is said to be like her father in several ways, one being that she never considers anybody else.
Though the sisters behave in dramatically different ways, they do not disagree on much in the novel, particularly when it comes to their opinions on their father's second marriage.