The stories we tell ourselves define who we are; analogous to snowflakes, every story is different. However the way we tell our story differs from the way others would tell it, for their version of our story is filtered through their story. The plot of an individual story is shaped by events beyond our control.
Tragic parts of the story can be remolded, or as John Dewey said, “Time and memory are true artist; they remold events to the hearts desire.” Myth making is a component of every story, so fantasy merges with reality. Usually the new revision is much more pleasing to the author.
Revising, reflecting upon the story thus far can be helpful; It can guide the author on the better ending to the next chapter. Each chapter should end with a revelation; a new beginning to the next journey for the next chapter should be an extension/growth from earlier parts of the book. If events go well the book will have a happy ending.
However, happy endings usually only happen in fairy tales. Reality does not easily lend itself to happiness or even equanimity. Many people live a life filled with excitement and drama. These concepts make stories much more exciting because these concepts make for the best stories.