Not every film is perfect. In fact, if you watch a film with the intent of finding faults, continuity errors or character discrepancies, you're likely to find something in every film you watch. Because making a film is hard work, and making everything come together as one complete organism - with no gaps, no bumps - is easier said than done.
Especially when dealing with time travel, as this list will demonstrate.
But time travel isn't the only plot hole theme that needs tackled and fixed, as action flicks, family animations and dramas are all culprits, too.
Be it issues with the setting of the film, the way characters interact, the way backstories are twisted to fit the narrative, no film is safe from the possibility of a glaring error. And in a time when the Internet is rife with people picking apart films for the world to see, it's now more obvious than ever when your film is missing something important.
The following list deals with these plot holes, but with the added bonus of their directors, producers and screenwriters coming forward with an explanation into how they came to be, and how they can be fixed for future viewings.