Music is a powerful tool for setting mood and evoking emotion. Filmmakers know this all too well. It’s no wonder the Academy Awards gives out Oscars for Best Music Score.
Try to imagine Darth Vader marching into a room of lined up stormtroopers without the “Imperial March” playing. Or consider the Lord of the Rings movies without the music. They wouldn’t be the same movies, and they certainly would struggle to evoke the same feelings.
As a dungeon master, you share much in common with a filmmaker!
Fleshing out your world, you move from premise to treatment and to something that eventually feels like a loose screenplay. Gathering your players, in many ways you are gathering your actors who will provide the dialogue and, with you as the director, bring your world to life.