Sally and Esperanza seem like an unlikely pair of friends. Sally's beauty and sophistication heighten Esperanza's feelings of ugliness and awkwardness. While Sally wears makeup and black nylons, Esperanza can't even keep her blouse clean. Sally likes to make out with boys; Esperanza would rather be one of the boys. Sally wants to get married; Esperanza wants to be free and independent.
The actions of the two girls mirror each other in an interesting way. When Sally agrees to kiss Tito and his friends in order to get her keys back, Esperanza doesn't understand their game. She shows up on the scene, ready to rescue Sally by force, if necessary. On the other hand, when Esperanza needs rescuing, Sally is nowhere to be found. Esperanza considers this an ultimate betrayal.
Sally's exaggerated sexuality is pretty understandable when you consider her father – a strictly religious man who seems to think that women are nothing but a source of shame for their families. He beats his daughter every time he sees her looking at a boy, because he's afraid she'll run off with someone just like his sisters did. The beatings are often accompanied by a refrain in which he denies his relationship to Sally, saying: "You're not my daughter."
Esperanza's Papa, on the other hand, is protective without being oppressive. The chapter "Papa Who Wakes Up Tired in the Dark" characterizes him as a hardworking, caring father, who sacrifices a lot for his family. He and Esperanza have a close bond – when his father dies, Esperanza takes on the role of parent, and holds him.