Every story is about relationships
Put simply, all stories are really telling about relationships.
Whether it’s relationships between people, people and things, people and animals, or any other combination—it really boils down to telling the growth of a relationship.
Stories are about conflict and change.
What changes a person?
Usually other people.
So, we see the conflict and change of the relationship through a story.
Summarizing Pete Docter’s explanation of the essence of a story in my own words.