Building the parts that will become the whole is difficult. Creating and understanding everything about the story is what makes the process memorable. Character histories, backgrounds and relationships, knowing the past, present, and future leads to some form of self-examination.
Therein lies to attraction to narrative fiction. We relate to well-developed characters because they present the illusion of pure cause and effect when it comes to being human. We know that we cannot trust, completely trust, our own experiences.
But we would like to.
That is one other benefit of suspending disbelief.