Making a single good, successful movie is difficult enough, but developing a franchise of films that continually go down well with critics and audiences alike is basically a feat of cinematic wizardry.
As such it's not uncommon for movie franchises, with all their moving parts and creative voices, to make huge creative missteps which threaten to doom them forever more.
What's less common, though, is franchises which repeat the same damn mistake twice.
We all know the famous quote about the definition of insanity being doing the same thing over and over again and expecting different results, which rather sums up the filmmakers, producers, and executives behind these undeniably successful franchises.
These 10 movie franchises, whether dead, currently on hiatus, or still thriving to this very day, all threatened their own existence by daring to make the same mistake twice.
From failing to plan ahead to taking a bold, bone-headed creative swing, killing off beloved characters, or pointlessly spoiling the plot in the marketing, these series all allowed the bad, stupid thing to happen twice - sometimes twice in a row, even.
Now, we simply pray they don't go for the three-peat...
10. Not Planning The Story Ahead - Star Wars
When you're building a gigantic, sprawling cinematic universe, it's incredibly important to have a firm handle on the fundamentals and a decent idea of where the story and characters are going for the foreseeable future.
This has been Star Wars' problem twice - once in a way it was ultimately able to weather, and another that has proven considerably more destructive to the brand.
When A New Hope was being shot, George Lucas had a lot of free-flowing ideas for future films but nothing that was set in concrete - a process which continued through production on The Empire Strikes Back.
Lucas didn't come up with Darth Vader (David Prowse) being Luke Skywalker's (Mark Hamill) father until he was deep into writing Empire, as contradicted Obi-Wan (Alec Guinness) telling Luke that Vader killed his father in A New Hope.
Far more embarrassingly, there's the infamous kiss between Luke and Leia (Carrie Fisher) in Empire, before they're revealed to be siblings in Return of the Jedi.
It's all a result of Lucas not having a firmly set plan for the major narrative and character beats, but on the balance of things he totally got away with it.
Less successful was the recent sequel trilogy, which suffered immensely from a lack of creative cohesion throughout.
The Force Awakens set a firm if unadventurous template, which Rian Johnson boldly shook up in The Last Jedi, the polarising reception to which prompted Lucasfilm to pivot for the retcon-heavy, pandering nonsense that was The Rise of Skywalker.
These films very clearly needed a road map, especially with billions of dollars up in the air, and the result is a trilogy of movies which, while hugely commercially successful, lack the cultural and merchandising power of the original three.
The prequels, for as disappointing as they were, at least understood the merits of a mapped-out throughline, ensuring the A-to-B-to-C storytelling mostly made sense.
If we end up with another trilogy of Star Wars movies - as, surely, we will - Lucasfilm first needs to settle on a firm idea of where things are going.