Update: I mapped 40 alternate endings for Holes in a notebook and just found the mistake I made for 3 months
I started a notebook back in January to map every way Holes by Louis Sachar could have ended, and I filled up 40 pages in a little spiral pad. Last week I flipped back to page 12 and saw I had Stanley running away from Camp Green Lake in almost every version I wrote, which is the exact opposite of what the book is about, since he grows by staying and digging. It hit me when my kid read page 12 over my shoulder and asked, quote, why does he keep running, he already knows he did nothing wrong, end quote. Turns out I was just swapping the ending scene and never changing the middle, so every ending felt flat. What's a small change in a book's middle that would really earn a different ending for you?