Why was Miss Spider satisfied when the peach rolled over Aunt Sponge?

Miss Spider was satisfied when the peach rolled over Aunt Sponge because it symbolized justice for Aunt Sponge's cruel treatment of James and the other creatures. The incident highlighted the reversal of fortune, where the once oppressed could now witness the downfall of their oppressor. Additionally, it provided a moment of amusement and celebration for Miss Spider and her friends, who were happy to see Aunt Sponge receive a taste of her own unpleasantness.