This question originally appeared on Quora. 
Answer by Mark Hughes, screenwriter and Forbes blogger
I think the films that were the biggest letdowns after the hype and potential and expectations were:
Rock of Ages -- Adapting a Broadway musical nominated for so many Tony Awards, praised by critics, loved by audiences, I expected at the very least to have a fun time. Instead, within a few minutes, I was cringing and wanted to leave. My wife and I kept giving one another incredulous looks and laughing in disbelief as it managed to someone get worse by the minute.
The Raven -- With a premise like this, there is no excuse whatsoever for not making a good movie. Edgar Allan Poe investigating serial murders that are based on his writing? How do you mess that up?? Arrrgh!
Dark Shadows -- I loved the original series, and loved the excellent 1990s revival series (which is on Netflix, so if you've not seen it but you love vampires and want to see a great Gothic vampire series, go watch it!). When I heard Tim Burton was making a film adaptation starring Johnny Depp, I expected a really great movie that was weird, dark, and expanded the whole portrayal of angst and out-of-place isolation of Barnabas. Instead, it was a goofy satire, and not even a very good one. Such a waste of talent and source material.
Those are the biggest disappointments. Now, I'd like to just mention one "mild disappoint" that's going to get rotten vegetables thrown at me. I liked this movie, I'm not saying it was bad, and it had a lot of even great moments and acting. But the hype surrounding it, and the praise that claim it had a near-perfect sense of time travel and that it was an instant sci-fi classic, all had me so worked up and expecting to have my mind blown. So in terms of expectations and buzz and potential compared to my honest reaction and feeling about it, this film has to be counted on my list of disappoints even though it's only mild and not an actually bad or awful film like the other three movie named above...
Looper has several HUGE plot holes and inconsistencies in the time travel concept. I've seen some attempts to explain it, but they just don't solve the problems and tend to overly complicate things. I'll go ahead and name my single biggest problem with the entire premise, just to make it clear why I had this reaction to it, so you don't think I'm totally crazy.
*SPOILER ALERT!!* STOP READING IF YOU'VE NOT SEEN THIS FILM AND PLAN TO SEE IT (WHICH YOU SHOULD, BECAUSE EVEN THOUGH I WAS DISAPPOINTED THAT IT DIDN'T LIVE UP TO MY GRAND EXPECTATIONS, IT'S STILL VERY GOOD AND EASILY ONE OF THE BETTER SCI-FI FILMS OF THE LAST SEVERAL YEARS)...
Okay, I hope you stopped reading if you want to avoid the spoilers...
We hear early in the film that someone called the Rainmaker rises up in the future to wipe out Loopers, having taken control of the whole criminal underworld somehow. We also hear that he has a fake jaw, from some injury in his youth. The Rainmaker clearly dislikes Loopers for some reason, and it's probably related to his fake jaw, since little details like that tend to be mentioned for a reason, right? Right.
Then we see Bruce Willis' original timeline -- he shoots his future self, takes the money and retires, eventually meets his bride-to-be, gets married, and has a happy life, then the Rainmaker comes along and starts wiping out the Loopers, and Willis' wife is accidentally killed in the process. Right? Right.
So Willis goes back in time to stop the Rainmaker, and of course in the process, we realize that Willis' actions in the past are what creates the Rainmaker in the first place -- Willis shoots the kid in the face (thus the fake jaw in the future) and is going to shoot the kid's mother in front of the boy, so in the future the kid's whole plan to kill the Loopers is to prevent his mom from being killed. The kid knows it was a Looper, that's all he knows, so his rein of terror is all to save his mom from Willis in the past. The film clearly sets this entire time loop up, and at the very end Joseph Gordon-Levitt (as young Willis) literally says that he realizes this is the start of the time loop that creates the Rainmaker. So the story all makes sense because Willis went back to stop the Rainmaker and actually is responsible for creating the Rainmaker after all. Right? WRONG! WRONG! WRONG!
Because Willis went through the time line without ever doing any of that stuff the first time, so where the hell did the Rainmaker come from in the original timeline? Remember, we see the entire original timeline where Willis kills his future self, takes the payoff, and lives his life with his wife etc. But the Rainmaker showed up ANYWAY, had a fake jaw ANYWAY, and is out to stop his mom's death at the hands of a Looper ANYWAY. So it cannot be possible that Willis' time travel events during the later film were all the real cause of the Rainmaker's creation.
The Rainmaker in the future clearly hates Loopers and the point of the story is that he's trying to stop some Looper from doing something, likely -- as part of the film's clear hints that cannot be ignored -- something related to the fake jaw the Rainmaker has. There's no way around it, the film's intention was to set it up so that the Rainmaker is trying to stop Willis, but since the kid didn't know who the Looper was who killed his mom, he has to try to take out ALL of the Loopers to keep it from happening. His fake jaw is from Willis shooting him in the face. This is all clear, it's obvious that's what the story was trying to say happened. And none of it makes any sense in light of the fact Willis didn't do any of those things in the original timeline.
That's the first glaring problem with the movie. But there are more.
Second major glaring problem that ruins the whole premise of the film? Well, ask yourself why Loopers exist. Remember what the film tells us, that it's almost impossible to kill anyone in the future, tracking devices and systems etc in the future make it impossible to get rid of bodies, so the only option is for the mob to send people back in time to be murdered and disposed of. The whole film depends on that founding premise. Right? WRONG! WRONG! WRONG AGAIN!
The Rainmaker takes over organized crime in the future, by KILLING EVERYBODY WHO IS A RIVAL. The film explicitly states he went on a rein of terror that wiped out the heads of organized crime and their enforcers. If your movie's premise depends on the idea that it's so impossible to kill people in the future that the mafia has to send people back in time to be killed, you can't then ignore that key premise and just say "some dude in the future started killing everybody who got in his way." Big, big flaw that undermines the film's most important premise.
So the film's entire concept about Loopers is undermined by the central conflict in the story with the Rainmaker. And the Rainmaker's entire existence makes no sense, nor does the entire series of events that start the plot moving (Willis wanting revenge on a Rainmaker who shouldn't exist). Those are pretty big problems.
But I'm not done, sadly. The mob uses Loopers to hide the killings, right? This is supposed to be some ingenious way to keep these killings from being discovered, and as we are told very clearly in the film, time travel is a major crime and maybe even bigger than the killings. Right? (You know what I'm going to say...) WRONG! WRONG! WRONG!
Because despite the fact that this whole Looper project and the use of time travel requires utter secrecy to work, LOOK HOW MANY PEOPLE KNOW ABOUT IT. Everybody knows who Loopers are, even a woman out on a farm who has no contact with the rest of the world. People are shown reacting to their Looper guns like "oh crap that dude must be one of those Loopers." So everybody in the past pretty much knows all about the time travel plot for killing people. And the film says that when the past changes, it changes the future, remember? So the mob using time machines to send bodies back to be killed by Loopers isn't a secret ... so why the hell does the plan even WORK? It makes no sense, since the film sets this up as some really important way of disposing of people without the government finding out, and then makes it clear that everybody including lonely farmers know about it.
And there's still more. The mob is very concerned about changing the past, remember? This is noted in the film, the whole thing about stepping on a butterfly and changing the future and all of that. You can't have some Looper's future self running around alive in the past, it could screw up the whole future!! That's a really big deal!! People from the future can't be allowed to change the past by telling anyone stuff from the ... OH WAIT, THE WHOLE LOOPER PROGRAM IS RUN BY A GUY FROM THE FUTURE WHO GOES BACK IN TIME AND THEN BUILDS AN ENTIRE ORGANIZED CRIME INFRASTRUCTURE OF LOOPERS AND BODYGUARDS WHO ALL KNOW ABOUT TIME TRAVEL AND THE FUTURE. And this leads to everybody ELSE in the past knowing about time travel and the future.
Considering how much they make a big deal out of not letting dudes from the future run around and alter the past, it's a glaring hole in the concept when there's this mobster from the future hanging out in the past and totally altering the past with knowledge about the future.
As for how they track down people from the future, there's some really bad inconsistencies there, too. Remember when Gordon-Levitt's friend Looper lets his future self escape? Remember how the mob grabs the past-Looper and starts torturing him by cutting him up, and his future self has his foot falling off and stuff? But they can't kill his past self, though, or it changes the future! Remember, they say they can't just kill him because they have no idea how that might alter the entire future (again, an idea undercut by the above points, but now I'm about to talk about another big problem...)? Okay, so if this dude suddenly had his feet and arms cut off in the past-version of himself, then the future version shouldn't even still be RUNNING AROUND. He should've instantly VANISHED, because there's no way that after he was cut up in the past he still had the same future life that ended with him coming into the past and RUNNING AWAY. Grabbing his past self and cutting him up should've instantly altered everything, so that his future self was sent back in time as an armless, legless dude shot down by another Looper (since the past self no longer could operate as a Looper, of course). We KNOW this is what really should've happened, because when Gordon-Levitt shoots himself at the end, the future self just BLIP! vanishes into thin air instantly.
Too much of the time travel concept was inconsistent and undercut major parts of the premise and ongoing story. After being told by so many film critics that the movie had an internally consistent time travel concept, and that it had a really clever and consistent way to resolve the conflict in the climax, and after hearing how great this film was and what a smart, consistent time travel story it was, I went in with expectations set way too high. I still enjoyed it, but through the whole thing I kept grimacing at the inconsistencies, and I frankly knew exactly where it was going with the whole "Willis is going to create the Rainmaker" thing as soon as he revealed his plan to find the Rainmaker. I even realized "oh he'll be the one to shoot the Rainmaker's jaw off." It was clear that's what the whole story was setting up, but it was equally clear that it made no sense whatsoever. So I ended up liking the film, but feeling let down that it had so many major problems with consistency and plotting.