The large story is one of the most reliable predictors of sprint failure. A story that spans more than half a sprint occupies the team’s attention, resists review, and tends to arrive at the sprint boundary in a state of near-done that creates exactly the kind of work-in-progress debt that sprints are designed to prevent. Teams know this. They continue to carry large stories because splitting them well is genuinely difficult and the techniques for doing it are not intuitive.