We Are Family

We could say the narrator's worried a better pet could be out there and call it a day, but if we dig a little deeper, we have to ask what constitutes a "better" pet. Arguably, it boils down to a pet that fits better with the narrator's family, a creature who will harmoniously reside for the rest of its days with the narrator and Kay and their parents.

Looked at from this angle, underneath the narrator's worry about identifying the perfect animal to take home is a struggle to identify what his family is all about (source). He isn't just wondering about furry and feathered critters; he's trying to make sense of himself and the people he lives with as he grapples with the array of pet possibilities.