9. Gravity Isn't An On/Off Switch - Passengers
It feels a bit unfair to single out Passengers (2016) in this entry, as many other sci-fi movies have also been known to fall back on this particular space lie. But, as their presentation of gravity is particularly questionable, they'll be our focus here.
In order to generate artificial gravity on the Avalon throughout the movie, the ship is constantly spinning at a high pace. That is until the ship suddenly stops spinning and gravity immediately becomes non-existent.
Yet, the ship wouldn't have just come to a screeching halt after spinning that fast through space, so the gravity wouldn't simply vanish in seconds. In reality, it would probably need sizeable breaks to stop it from moving.
It must be said, though, that the film does depict what would happen to water in a zero gravity environment quite well.
As the gravity disappears, Jennifer Lawrence's Aurora Lane is swimming in a pool. The water then begins to rise up into the air and forms itself into a ball, which is what would likely happen in that situation. This leads to her desperately trying to escape the water until the ship begins to speed back up again.
However, it again would require a lot of force and time to get such a large ship spinning fast enough to create artificial gravity, so it wouldn't be a case of everyone immediately falling back to the floor like gravity is an on/off switch...as we see in the movie.
Saying that, if the film had realistically presented how long it takes for gravity to be fully re-introduced, Lawrence's Lane would have likely not made it out of her water blob alive. Which would have been a bit of a downer.