Sadie is most notable for being Katie's best friend. They do everything together, including wearing the same outfits (which Katie sews herself). Like Katie, Sadie is a sensitive, cheerful, and sweet-natured girl. Sadie shows herself to be rather emotional, even more so than her best friend. She cries whenever she is upset, and lashes out at those who cause her anger. She is boy-crazy and when she grows attracted to someone, she and Katie will fawn over him endlessly. Sadie can be considered the more logical one between the two. Her biography even states that she "thinks with her head", contrasting to Katie who "thinks with her heart". Sadie was even the one who came up with the idea of their summer job, which involves making their own ice cream and selling it at the pier where they live. It is implied that Sadie is the more logical of the pair, but her silence during her time without Katie may imply that Sadie is the less independent of the two