Stakes

Without stakes an audience watches events happen. With them, an audience waits to find out. They can be money, time, reputation, physical risk, a deadline, or something as small as whether the thing you built actually works. Stating them early is what makes them do any work. Hold the consequence back until the end and you have written a twist instead. Scale matters less than clarity. A small risk explained clearly beats a vague large one, and stakes the viewer does not believe are worse than having none at all.