John Carpenter explains that the secret to composing and performing Halloween came from his father:
He was a music professor. He taught me 5-4 time when I was 13 on a pair of bongos of all things. And 5-4 time is bop, bop, bop. Bop, bop, bop. Bop, bop. Bop, bop. Bop, bop, bop. Bop, bop. Bop, bop, bop. Bop, bop. So I simply sat at the piano and I rolled octaves, so that’s how it came about. It was simple, repetitive and, like you said, causes tension in the audience. They’re waiting for something to change. [...] It puts you in a little bit of discomfort emotionally. Why is this not evolving and changing? It’s repeating over and over and over again.
By the way, Carpenter got into the movie business to make Westerns, but Westerns died.