Some mornings I wake up, read through my notes on a job, and then very methodically work through a carefully defined problem -- sharpening the character's misbehavior, or building stakes, or clarifying the conceit. That kind of thing. It all works just like it's supposed to. Story problems obediently present themselves just where you'd expect to find them. And they respond to your treatment just the way they should.
Then there are other times when problems pile up on each other and it's difficult to see the elegant solution underlying all the big issues. There's a big knot somewhere in the middle of the script, and you don't know which end to start picking at. This is when the f***-it copy comes in handy.
A f***-it copy is a duplicate file where you are officially allowed to f*** up. You're allowed to play. You're allowed to try things out. You can pull out a character and see if the story still balances out. You can pull out a scene, or reverse a polarity, or try the easy solution. You can try simply playing with it -- as far away from screenwriting orthodoxy as you please. And when it doesn't work -- f*** it.
F***-it copies are never the final solution, but they almost always teach you something you didn't know before. Why? Because you are utilizing one of the most under-taught skills of any kind of writing, including screenwriting:
Scripts are like any other big project. The more possibilities you look at, the better the finished work. It's within your power at this very moment to see what your script looks like without all that dialogue. You can flip scenes around and take a page out and let your characters fail and everything else. You're modeling your story. And your computer doesn't mind. It will store as many f*** it copies as you can come up with.
I often wonder why we don't teach this skill more. I suspect it's because most screenwriting gurus learned their craft either on a typewriter, or from someone who used a typewriter. Hard and fast structures (and ideologies about what goes where) were a safe bet. I remember rejecting a lot of gurus fairly angrily when I read them. Why must the Refusal of the Journey go here? There's nobody going into the Innermost Cave in my script. Anybody telling you that your script MUST be shaped around their methodology is just selling books.
But that same methodology is absolutely, utterly, invaluably useful as a modeling tool. You'd be foolish not to try it out. If it works, great. If it doesn't you'll still figure something out. And well, if it doesn't work at all, then f*** it. You spent the day writing and thinking about your story.