Strictly speaking, the world is just one big stealing machine, in which artists and creative types take an idea from the generation that influenced them, make a few changes, and send it back out into the world with a huge "look at this amazing idea I made up" sticker plastered across its face. Naturally, the world applauds this kind of behavior.
Which is this writer's way of saying: everybody steals everything. Which is fine, given that old ideas give rise to new ones. Directors, in fact, take elements and aspects from the things they love all the time, and aren't usually shy to admit it. Take George Lucas, who borrowed the serial aesthetics from shows like Flash Gordon and re-interpreted them as Star Wars. Or Quentin Tarantino, whose entire career hinges on his reputation as a kind of hip-hop movie director, stealing things from his favourite filmmakers and twisting them into exciting new wholes.
As far as snatching a few minor plot ideas go, then, most of us can probably agree that it's generally considered to be okay (in moderation, at least). But how far does innocent "borrowing" need to go until it just becomes fully-fledged stealing of the criminal kind?
Here's 8 iconic movies you might be shocked to learn ripped their entire plots from other works of fiction. In some cases, we're seriously surprised that the creators of the original works were so indifferent to all the, um, theft.