Making a single hit movie is one thing, but keeping that momentum rolling for an ongoing cinematic franchise is a whole other challenge, and one which often causes once-promising movie series to eventually sputter out.
While in many cases movie franchises simply die off due to declining audience interest, there are sometimes instances where a single creative decision clearly marked the series' decline.
This can be a business decision, such as shooting for a squeaky-clean family-friendly rating or hiring a certain unqualified filmmaker, or a creative one, such as killing off a beloved character or taking the story in a wholly un-commercial direction.
Whatever the decisions were, in each case they drained each series of their remaining value, whether critically or commercially (or both), ensuring that future prospects look rather dim indeed.
That's not to say these franchises can't ever be redeemed - just look at how successfully Halloween was revitalised with its first good movie in literally decades - but simply that their boom period of success is long gone, and it'll take some major leg-work to get things back to a satisfactory level...
10. Killing John Connor - Terminator
Though it's fair to say that the Terminator franchise has continually fallen short of James Cameron's two original classics, the first three sequels at least didn't do anything unforgivable enough to actually leave fans turning away in droves.
But then Terminator: Dark Fate happened.
Though on paper Dark Fate had all the potential to be the best Terminator since T2 - what with Cameron helping write the story and Linda Hamilton returning to the series - it soured many fans completely in its opening scene.
Dark Fate, which ditches the three prior sequels and positions itself as a direct follow-up to T2, kicks off with a young John Connor (Edward Furlong) being assassinated by another T-800 (Arnold Schwarzenegger) sent back in time by Skynet.
As ballsy as it was, it didn't really serve much dramatic purpose beyond clearing the table so this new movie could basically soft-reboot the series with a new saviour character, Dani Ramos (Natalia Reyes).
Given that fans are deeply attached to the John Connor character, once word of his death got out many simply opted not to catch the film in cinemas at all, resulting in Dark Fate becoming the lowest grossing Terminator film since the original and resulting in losses of around $130 million.
With several planned sequels immediately cancelled, the series has effectively been put on ice for the foreseeable future, given its shaky financial viability in the blockbuster realm.
By terminating John Connor, the series also terminated itself.