Flash-forward

You take a moment from later in the video and drop it into the first 10 seconds. The finished build, the reaction shot, the second everything falls apart. Then you leave it there and begin properly. It works because it is evidence, and evidence sits in a different currency from a promise. Two ways this goes wrong. Use the actual payoff and you have already spent it, so choose a clip that raises a question and leaves it hanging. Show something the video never delivers and the retention graph will register the betrayal about a minute later, along with the comments.