Showing (instead of just telling) can win converts
Frank Miller, author of the Sin City series of graphic novels, told his friends it wouldn’t be possible to make a live-action film version of these books. He resisted all offers from Hollywood until young director Robert Rodriguez approached him with a unique proposal: come and watch him shoot a scene from one of the books for a day. If he liked what he saw, they would make a deal to give Rodriguez the right to make a film of Sin City. If not, Rodriguez would give him the short film from that day as a souvenir and that would be the end of the discussion.
Miller took him up on it. He went to Austin, Texas, and watched actors including Josh Hartnett play a scene from one of the short stories from the Sin City books in front of a green screen. On the same day, Rodriguez edited the footage and added music and special effects to complete the 3-minute film.
Miller was convinced. Rodriguez and Miller became co-directors of the film, which came out in 2005, grossing more than £100 million worldwide and spawning plans for a sequel.