Rey mentions the quicksand to BB-8 earlier.
Writer #1: “Hey, we need to disappear Poe’s TIE fighter after they crash.”
Writer #2: “Have Rey say something about quicksand in an earlier scene. Done.”
Writer #1: “Awesome! Lunchtime.”
Same deal with Finn and his saber skills.
Writer #1: “How can Finn possibly fight Ren in a saber battle and not get sliced to pieces?”
Writer #2: “Show him fighting a bit earlier with a Stormtrooper who has a saber-like weapon.”
Writer #1: “What value would sword fighting be to a Stormtrooper?”
Writer #2: “It’s Star Wars, man. Just shut off your brain and enjoy the ride.”