Subplots are a vital part of pretty much any movie - you have the ever-important A-plot which keeps driving the film along on the surface, combined with smaller narrative threads which, in theory, compliment the overarching story.
Not all subplots are created equal, of course, and it's easy for writers to overstuff even good movies with a few flabby side-quests too many, causing the film to rather outstay its welcome.
And while we've all sat through wonky subplots in good or even great movies - the Canto Bight diversion in Star Wars: The Last Jedi, for instance - what about those times where an unexpectedly strong subplot finds its way into an otherwise bad movie?
These 10 films, whether disappointing entries into existing franchises or entirely original misfires, all struck gold with a single subplot which temporarily brought the movie surging to life.
While the rest of the film wasn't up to snuff, these scenes provided viewers with temporary relief, allowing them to savour the intelligent storytelling, fine character work, and sheer honest-to-God entertainment value, fleeting though it may have been...
10. Jigsaw Targets Corrupt Cops - Spiral: From The Book Of Saw
The latest Saw film, Spiral, may have ultimately been a crushing, predictable disappointment, but it had one undeniably excellent idea at its core, that the new Jigsaw killer was targeting corrupt police officers.
This was in fairness a narrative thread first raised in the previous film, Jigsaw, but Spiral took it in an altogether more intriguing direction, by having the new copycat killer specifically putting cops in traps who were abusing their power.
As dissatisfying as the reveal of the killer's identity ultimately is, the reasoning behind their choice to follow in Jigsaw's footsteps - their own father being killed by a corrupt cop - is certainly a thoughtful and timely one.
In an age where the police are under more justified scrutiny than ever in reality, examining the issue through the lens of a grisly horror film was nothing if not inspired.
It's just a shame that most everything surrounding this neat subplot was the same old standard fare Saw nonsense.