The trailer can make a film promise something its full story never intended to deliver.

A trailer is assembled to promise, and the promise can belong to a different film than the one that exists. Nothing was fabricated; the pieces were arranged to imply something the whole never intended. Selection alone can create a false impression.

Watch for the same thing in how anything is previewed to you, a job, a product, a person’s account of their own project. Ask what the full version contains and whether you have seen anything that was not chosen for effect. And be careful when you introduce your own work, since a compelling preview that oversells is a debt you pay later.