Everyone likes a good "What If...?" scenario. Who doesn't?

There's an old joke in Hollywood that goes, "How do you know that you've landed a part in a movie? When you walk the red carpet at the premiere of that movie." It just means that, until the movie premieres in front of an actual audience, things can always change. Hollywood is infinitely adaptable. When you're dealing with psychopathic studio executives, devious directors and pathologic producers... Well, anything is possible. And the loudest voice at any meeting inside of any studio is always money.

Actors and actresses are always being shuffled around even after a movie begins shooting. The actor Eric Stolz was Marty McFly in the movie "Back to the Future" until he was replaced weeks into shooting by Michael J. Fox. Timothy Dalton was chosen as the iconic British spy James Bond only because Pierce Brosnan couldn't get out of his contract for the television show "Remington Steele" (although Dalton's tenure as 007 was decidedly short and, admittedly, Brosnan would go on to play the role anyway). Tom Selleck was cast as Indiana Jones but couldn't get out of his contract for the television show "Magnum P.I.," a development for which Harrison Ford will always be eternally grateful. James Remar was forced out of the movie "Aliens" because of a drug arrest and replaced by Michael Biehn. And the list can go on and on and on...

The phenomenon isn't reserved for just the cast, though; Movie directors have been replaced mid-stream during a movie's production as well. Richard Stanley was practically chased off the set as the director of the infamously plagued "Island of Dr. Moreau" (returning clandestinely as an extra) and replaced by John Frankenheimer. The actor Clint Eastwood forced director Philip Kaufman off of the movie "The Outlaw Josey Wales." And how many times has a Pixar movie began with one director only to wind up with another part way through? Well... How many fingers do you have on both hands? Close enough.

It's one thing to replace an actor or a director. With actors, the concern is just making sure that the costumes fit. Actor Vernon Wells was a last-minute replacement in the movie "Commando" and the reason why some of his garb appears to be more snug than usual is because the person that he was replacing had a decidedly smaller frame. With directors, you have to make sure that the footage shot meets the vision. On "Sinbad of the Seven Seas," director Enzo Castellari was let go after submitting hours of mostly unusable footage. Luigi Cozzi was brought in to salvage the mess; It's the reason why the movie went from having a conventional narrative and adopted the 'bedtime story' motif (the same type of device used in the movie "A Princess Bride")... Because it was the only way to piece together the fragments of the movie that still resembled... Well, a movie.

Yet, beyond actors and directors, perhaps the hardest role to replace during a production is the music composer. Composing music is hard. Scoring a screenplay has been often compared with flying in complete darkness, then having to land the plane quite suddenly in an entirely different location from where you were originally told. And that's if you were fortunate enough to be hired right from the start. James Cameron, while directing he movie "Aliens," didn't understand the need to finalize scenes so that they could be worked on by other crew in order to add special effects and music. James Horner, the composer hired to score his movie "Aliens," became so frustrated that he nearly left the production. The resulting music was such a jumbled and rushed mess that Horner was forced to use unused music from a prior movie that he scored, "Star Trek II: The Wrath of Khan," in order to complete his assignment.

Perhaps the largest "What If...?" in movie production are that of rejected movie scores. These are scores that were fully written and performed but, for one reason or another, were either rejected by the director, the studio or some other person with considerable influence. It's no small feat to turn down an entire score because movie scores aren't exactly cheap nor are they quick to produce. Artists also aren't keen to working very hard only for their product to wind up in a vault somewhere, gathering dust. The artist known as "Sting" was notoriously perturbed when over a year's worth of his hard work to create original songs for the Disney animated film "Kingdom of the Sun" was scrapped because the project went into turn-around to eventually become "The Emperor's Last Groove."

Arguably, the most famous rejected movie score of all was when director Stanley Kubrick, a notorious perfectionist, fell in love with the temporary music that he had been using while making the movie "2001: A Space Odyssey" and used that music instead of the one composed by Alex North. North only learned of that his score had been rejected when he watched the premiere of the movie.

Yet rejected movie scores abound and perhaps one of the more prominent ones is Gabriel Yared's "Troy." Having worked on the film score for over a year, his score was tossed when test audiences found that the score was too "old-fashioned." Given that the movie is about the famous battle between the Trojans and the Greeks (yes, the one with the wooden horse), the reasons for rejecting the score as 'old-fashioned' is more than a bit ironic. James Horner wrote the replacement score in a matter of weeks and, with all due respect, it shows.

Thankfully, Yared's score holds up quite well when listened to by a more intelligent audience. Given that the film wasn't exactly a financial hit (even with it's 'new-fashioned' score from Horner), one must wonder if Yared didn't have a smug sense of satisfaction for having not been a passenger on that sinking ship. The rejection hasn't seemed to hurt Yared's career and Horner's... Well, his was cut short because of a small plane crash in 2015.

Movies and their scores are said to be made for one another and only for one another. Would "Chariots of Fire" have succeeded if Vangelis hadn't scored the film? Would "Blade Runner" be the cult classic if Vangelis' score was rejected for someone else's? Would "Troy" have brought about a renaissance of old-fashioned "sword and sandal" epics if it had been attached to Yared's score instead of his replacement's?

Everyone likes a good "What If...?" scenario. Who doesn't?

https://www.youtube.com/playlist?list=PLF8IjBSQmQ-Ahu2RTDk83Yo4CF1QAJWsr