A phenomenal amount of effort goes into making even the worst movie, but regardless of whether a film is good or bad, many filmmakers will endeavour to include sneaky hidden details for viewers to catch.
These can range from deviously sly references which make viewers reconsider the entire movie through a new lens, or simply be playfully insignificant visual gags for attentive audience members to look out for.
Thanks to incredible communities like /r/MovieDetails - from which many of these entries originated - keen-eyed fans who catch even the most minor detail are able to share their findings with the world, often resulting in it going viral on social media.
Now, these 10 details won't make anyone rethink their respective movies, and they are by their sheer nature "unnecessary" and low-key, but they nevertheless prove the immense level of thought that goes into aspects of filmmaking most audiences simply take for granted.
The fact that we've seen these movies, whether stone-cold masterpieces or more modest cult classics, potentially dozens of times and haven't noticed these stunning-yet-slight details is a testament to how impressively layered cinema can be...
10. Batman's Face Is Visible In The Mirror (Or Is It?) - Joker
Todd Phillips' Joker may be less a superhero movie than a dramatic thriller that happens to take place in the world of DC Comics, but that doesn't mean it's above including some visual Easter eggs nodding to the wider franchise.
Batman doesn't physically appear in the film at all, but there nevertheless seems to be a devilishly clever reference to the Dark Knight in the film's very first shot.
As the camera dollies forward towards Arthur (Joaquin Phoenix) sat in front of a mirror, there's a point at which the mirror creates a recognisable visage of Batman's iconic cowl.
Two lights in the mirror are the distinctive white eye slits in Batman's mask, while a pillow hanging at the top of the mirror creates a split for the mask's distinctive ears.
Fans have debated whether this was an intentional Easter egg or not ever since the movie's release, though the fact that it's become a viral sensation ultimately makes Phillips' intent - or not - beside the point.
Given the Joker's obsession with Batman, and the common inference in DC comics that the two rivals are mirror images of each other, it's a fitting visual all the same.