A truly great teaser or full-blown official trailer is supposed to ramp up the excitement for an incoming picture, giving film fans no choice but to dig down into their pockets and pay their hard earned dollar to witness the action on the big-screen.
Hell, a really well executed one can even take a project that next to nobody was even remotely interested in beforehand and turn it into a simply can't miss affair.
However, in the case of the following chunks of marketing gone wrong, it's safe to say that all these trailers did was either put off those deciding on what to take in next at their local theatre or sell folks a concept that was entirely different to what was ultimately sent their way in the finished movie.
Thankfully, in each and every one of these instances, the actual end product was vastly superior to the shoddy teaser footage and often bizarre sequences that were thrown together in these lacklustre two-minute advertisements.
But that still won't change the fact that you would have been forgiven for initially thinking about giving the following eventual hit flicks a miss after being put through the all-round awfulness on show in these particularly dreadful trailers...
10. How To Train Your Dragon
It's often forgotten just how underwhelming the first look at Dreamworks' first-ever How to Train Your Dragon animated flick actually was.
This may have been the same studio that brought folks everything from the Shrek to the Kung Fu Panda franchises, but the initial look at the first big-screen outing for Hiccup, Toothless, and the rest of the gang just felt like another forgettable family caper destined to be forgotten about like the prior year's so-so Monsters vs. Aliens picture.
That Jay Baruchel-narrated early glimpse into the lives of the folks of Berk, and their daily struggle with fire-breathing pests, barely highlighted just how much of a charming and unexpectedly deep tale was heading fans' way. And the consistently gorgeous animation that would eventually become a trademark of the franchise is also largely undersold here in favour of focusing on some of the poorest one-liners present in the entire feature instead.
Thankfully, the promise of an all-star voice cast consisting of the likes of Gerard Butler, Jonah Hill, David Tennant, and more was enough to convince most folks to give this dragon-stuffed future smash hit a chance. But many quite understandably found themselves wondering what all the fuss was about after witnessing this somewhat flat first look.