Growing up as a driver's daughter and thinking of herself as a "low class person" has caused Susan to feel inferior. As a result, Susan has always had a wish. She wished that she can become someone like Sophie because she always believed that as long as she can become Sophie, then she would definitely be happy. Under this type of a psychological shadow, Susan fosters the behavior that as long as Sophie has it, then she must have it too. From childhood to adult, this is the way that Susan treats Sophie. Sophie knows but she continues to remember the words of her mother to regard Susan as her real sister and not to tell anyone that Susan is an adopted child. Moreover, Sophie believes that Susan must be like this because of her background and as a result, she didn't haggle over the matter with Susan.