The genre of sci-fi is all about transporting audiences to far-flung worlds and allowing them to see things they simply cannot in "real life."
But canny genre filmmakers also know when to hold things back, to take advantage of the classic maxim that less is more, that viewers are often better off filling in the blanks in their own minds.
Often a director's ideas can be bigger and more ambitious than their budget can support, or perhaps the technology simply isn't there yet to realise those ideas as fully as they might like.
That's why just some of these 10 sci-fi movies should never be paused - elsewhere, you'll subject yourself to disturbing unconscious images, bizarre directorial gaffes, iffy technical shortcuts, and everything else in-between.
Collectively, these 10 freeze-frames either strip the mystique away, are honest-to-God creepy as hell, or might even have you questioning your own hold on reality.
As much as high-definition and 4K video releases are a wonderful thing for preservation, there's also the understandable sentiment that they can often remove that intriguing layer of fog between director and viewer, by bringing those pesky flaws to the crystal clear forefront.
Most of these movies are good - or at least interesting - regardless, but you're advised to just keep watching and not fixate on the minor details...
10. The Burly Brawl CGI - The Matrix Reloaded
Though The Matrix sequels are impressive technical showcases, there's nevertheless one massively divisive set-piece in The Matrix Reloaded, and that's the "Burly Brawl," in which Neo (Keanu Reeves) battles dozens of Agent Smiths (Hugo Weaving) at once.
It's a fun scene with some neat fight choreography and an amusingly unhinged performance from Hugo Weaving(s), as long as you don't stop to fixate on the technical minutia of it all.
Even back in 2003 when the film came out, fans were complaining about the uncanny valley CGI used to execute the fight.
This was with regard to both the video game-y acrobatics performed by Neo and the Smiths and also the fact that Hugo Weaving's likeness was awkwardly pasted over his stunt doubles' faces in post-production.
In motion it's noticeable but tolerable, yet if you stop to pause any piece of the fight where faces are clearly visible, there's a hideous, rubbery sheen to them, making the entire thing feel like, well, a simulation.
This has only become more of an issue with each higher-fidelity version of the movie, particularly the most recent 4K UHD release.