A discussion with another writer brought today's topic to mind. She told me she selects background music with specific reference to the genre in which she's writing. For example, if she's writing fantasy, she'll play music from a movie in that genre, or general music that focuses on that sort of theme. She'll even tailor the music to suit the specific scene (so that, say, a battle scene will involve fairly martial, warrior-type music, perhaps from Scandinavian thrash metal groups). I don't take it that far, but I realized that I do pick music to write to so that the former "fits" the subject for the day. If I'm writing a battle, I don't play lullabies!
That started me thinking. In cinematic entertainment, the theme music and sound effects often make or break the movie. Who could watch, say, Tom & Jerry cartoons without them? Their absence would ruin the cartoons. See (and hear) for yourself.
In a more serious vein, think of "The Lord of the Rings" trilogy. The music is so intimately a part of its portrayal that it's impossible to imagine the movies without their soundtrack. That can be said of many movies, of course, but it's particularly true of the LOTR trilogy. Here's a video containing the entire soundtrack, labeled as to scene. (You'll find the list, complete with timestamps, at the original YouTube listing). Pick a couple of scenes you know well, watch them on YouTube by searching for them (or use your own copies of the movies), then listen to the music alone (on this video) without watching the visuals. Both are so intertwined that neither completely makes sense without the other.
Definitely makes you think. To what extent are our lives themselves framed by their "soundtrack" - the "theme music" to our everyday lives? Take a big-city dweller. If you took away the sounds he was used to - traffic, car horns, the hustle and bustle of so many people all around him - would his life be the same? Would he seek to "insulate" himself from, say, country sounds by recreating "city sounds" around him? Is that why so many holiday resorts resemble nothing more than the same overcrowded, noisy cities from where they draw their clientele?
That's also a thought for writers. When we write, are we subconsciously composing the "theme music" for our scenes by selectively using words? Are we choosing them for the way in which they resonate with our readers, the emotions they evoke, the reactions they produce?
Food for thought.