In a way she actually preferred Peter to other people because of this. He always acted out of intelligent self-interest.
In "Ender's Game," the protagonist Ender Wiggin reflects on his relationship with Peter, his brother. Ender finds that he appreciates Peter for his distinct approach to interactions, as Peter consistently makes decisions based on intelligent self-interest. This characteristic sets Peter apart from other individuals in Ender's life, making him someone Ender can relate to in a unique way.
This preference underscores a complex dynamic in their relationship, as it reveals the depth of Ender's understanding of motives and interpersonal dynamics. While others may act out of various motivations, Peter's clear, self-serving logic resonates with Ender, presenting a stark contrast to the ambiguity he often encounters in others.