Behind-the-scenes drama on a movie set is never a good thing.
Where there are creative differences, arguments, or spats between the filmmakers and the studio, there's usually an incoherent final product or a movie that lacks a focused, singular vision.
Scenarios like this have become extremely prevalent as of late. 2015's awful Fantastic Four reboot is notorious for its extensive reshoots and quarrel between director Josh Trank and 20th Century Fox, and more recently, Lucasfilm's Han Solo spinoff lost its directors with just a few weeks of shooting to go - though the quality of that particular film remains to be seen.
However, some films can overcome these problems and defy the odds, delivering something that isn't just successful in terms of quality, but also makes plenty of cash and receives heaps of critical acclaim.
Some of the most famous movies of all time suffered a whole host issues during production, from replacing lead actors and switching directors to rewriting and reshooting entire chunks of the story, and the fact that they turned out as good as they did is nothing short of astounding.