There is no more important part of the movie marketing cycle than the trailer, because no matter how cool a film sounds in theory, it's the eye-catching imagery that's ultimately going to get butts in seats.
The Hollywood marketing machine is of course hell-bent on getting your ticket money at any and all costs, and so an entire sub-industry is built around the art of creating trailers that will appeal to your dopamine receptors.
And there isn't a film fan among us who hasn't been suckered in by a beautiful, energetic, hilarious trailer which promised a great time at the movies, only for the final film to be a bewildering disappointment.
Inspired by this terrific recent Reddit thread, these 10 movies remain some of the most impressively marketed of all time, and even years or decades later, their trailers remain a textbook example of how to market a film to the masses.
Yet the movies themselves remain a whole other matter, falling far short of the film the trailers sold and in turn leaving millions of viewers crushingly disappointed.
The lesson here? Take even the most brilliantly composed trailer with a truckload of salt...
10. Terminator Salvation
Never underestimate the power of Nine Inch Nails to make basically anything seem extremely cool. The first trailer for the fourth Terminator film, Terminator Salvation, was backed to the industrial metal band's brilliantly fitting "The Day The World Went Away."
The moody track was the perfect accompaniment to showcase the movie's grim, post-apocalyptic visuals, which combined with the gritty presence of Christian Bale's John Connor and a bevy of chaotic action, suggested fans would get the full-throttle future war movie they'd been craving since James Cameron's 1984 original.
Terminator Salvation wasn't terrible, but it was a massive disappointment all the same - appropriately bleak but largely lacking the gallows humour of the Cameron-directed first two movies.
Furthermore, Christian Bale was surprisingly bland as Connor, the CGI-soaked action underwhelmed, and the revelation that Marcus Wright (Sam Worthington) was a human-machine hybrid was bafflingly treated as a huge twist despite being spoiled by the trailers.
Alright, that last point isn't really the movie's fault.
Even so, Salvation boldly tried to prove the series' viability without Arnold Schwarzenegger - who only lent his CGI likeness to a T-800 model that briefly appears in the film - but instead served up a strangely soulless sequel far from the promise of that gorgeous trailer.