For a story to rivet the reader, the characters must change from evil to good, happy to sad, selfish to compassionate, or a similar change. Otherwise, the story reads like a bland planner entry. Short stories, in particular, must show the change quickly. Flash Fiction under 500 words needs the reader to understand the main character is a lout and will become less of one by the end.
Guarantee: if a writer finds a story or character stuck, likely nothing has changed in a while.
This is why there are so many worksheets and tools aimed at showing how a character matures, changes, or fails to change. All of the possibilities are laid out so when the writer gets stuck, they can go “Ah Ha”. I wondered what happens next.
I have mentioned I used to pants along hoping for character insight to fall down from heaven. Inspiration does fall down on my keyboard. It just happens to arrive in a character sheet.
Short stories also benefit from this approach. The character must make a change or the story must take the reader down a path with a hidden surprise. Otherwise, the whole story lacks any tension and fewer readers.