People are molded and shaped by events, other individuals, and the environment in which they live. As people age, their ideas and perceptions of the world can change as can their reactions to events that occur. This fact is exemplified by Catherine Sloper (Olivia de Havilland) in William Wyler's 1949 film The Heiress, based on Henry James's 1880 Washington Square.
At the beginning of the movie she demonstrates her kindness and naiveté. She does exactly what her father (Ralph Richardson) tells her and strives to please him. She is a quiet and meek girl and allows her father to walk all over her. Even when she shows off her dress for a party and he comments how the red color was better on her mother, she smiles and goes on despite the undeniable cruelty of the comment.
Another example of her devotion to her father comes after she falls in love with Morris (Montgomery Clift). Despite her father's snideness towards Morris, she insists that Morris be kind and that there is some way to win Dr. Sloper's approval of the union. She even agrees to put off her marriage and leave her love for six months for Europe. She also sees nothing but good in Morris. She honestly believes that he loves her for the person she is and not her fortune.
Upon her return and her discovery that her romantic choice will never earn her father's approval, and nor will she, Catherine decides to defy him and elope with Morris. Even after hours of waiting in vain for Morris to wisk her away, she still does not realize that he has abandoned her because she can no longer provide him with the life he had pictured.
The breaking point comes when Catherine's Aunt Lavinia (Miriam Hopkins) tells her the reason Morris has abandoned her. After she realizes, that both men she idolized have let her down Catherine transforms into a much harder and more bitter version of herself. Even at her dying father's weakest moment, she shows no kindness or sympathy to him. It seems as if she accepts and resigns herself to a life of loneliness.
When Morris returns ready to devote the rest of his life to a marriage with Catherine and her money, she teases him with a pretend happy ending and then turns him away quite coldly. She has learned how to cruel and hurtful by her father and then by Morris when let her down. Her hope in people has been ruined. Catherine has gone from being kind and unassuming to being cold and vindictive. In the end she has become the people who hurt her.