1. What the Story is About — This should go without saying, but occasionally writers do forget what kind of story they started out with and write an ending that belongs to a different genre. It’s an incredibly dissatisfying experience for a reader. For example, the critically praised movie The Dark of the Sun begins as a very interesting adventure story about a mercenary racing Congo rebels for a treasure in diamonds. However, the end of the movie forgets the plotline and concentrates exclusively on the main character’s internal journey. The ending forgets to answer critical questions (such as, did the rebels catch up with him? did he get away with the diamonds? did he make the deadline set by his employers?). The questions setup by the Inciting Incident at the beginning must be answered by the ending Climax.
2. Who Needs to Change — This is subtler than the first item on the list, but just as vital to reader satisfaction. The problem doesn’t even look like a problem for probably half the story, but it comes into glaring relief at the end. For example, suppose the story focuses on how the main character can’t let go of the past, and how her inability to let go of the past creates problems between her and her children. Her children tell her to move on with her life, other characters tell her to let go… naturally, readers assume character growth for her will be her letting go of the past and moving on with her life. That’s the happy ending readers expect, it’s what they focus their emotions on and root for to happen. But, no! The writer forgets who needs to change. At the end, the children suddenly change and everybody lives happily ever after. Because this is not the ending anticipated, readers experience an emotional disconnect from the resolution. If a story makes a big deal about a certain character flaw in the protagonist, that needs to be the area of change at the end.
3. Actions Have Consequences — If events don’t have consequences, then they don’t belong in the story. Protecting the chain of cause-and-effect logic is what saves readers from confusion. For example, suppose the main character is a superspy who goes on a mission to recover important computer data. There’s a big, exciting scene where she gets the data—lots of conflict, lots of nail-biting suspense. When she gets back, it turns out the data is worthless. This is a simple goal-defeated-by-obstacle moment, but without a consequence (such as, her partner is injured and can’t join her next mission) it could be removed from the story without being missed. The same could be said of a character-driven story where the heroine discusses her plight with friends, then goes home and discusses it with her family, then goes on vacation and discusses it with the hotel staff. Unless each dialogue scene has a unique consequence, it’s just so much stuffing and not enough turkey.