In the introduction to Bagombo Snuff Box, Kurt Vonnegut discusses psychiatrist Edmund Bergler's claim that "most writers in his experience wrote to please one person they knew well, even if they didn't realize they were doing that. It wasn't a trick of the fiction trade. It was simply a natural human thing to do, whether or not it could make a story better."
Vonnegut figured out that he wrote for his sister, Allie. "Anything I knew Allie wouldn't like I crossed out. Everything I knew she would get a kick out of I left in."
This concept is also reflected in one of his "Creative Writing 101" rules: "Write to please just one person. If you open a window and make love to the world, so to speak, your story will get pneumonia."
I'm curious . . . who do you write for? Who is your audience when your writing flows?
