I have written short stories and song lyrics, and how it eventually turned out was going to be in the moment. The crowd I used to hang out with, functioned in similar ways. Someone said something, either sober or drunk, and it was set in stone. But yes, sometimes it takes a while. Often there's that "never satisfied" gun barrel at the back of the head, demanding revisions.
Thematically, I am sort of limited... Death visited me when I was eleven years old, and from the next year, all the "normal" music that I could tolerate, was what I was familiar with up to that point. Political, philosophical, emotional, everything I could listen to, had to have certain rhythm, melody and frequency. All my pocket money I ever got I spent on tapes, later in life, all I could spare, on CDs. I was surrounded by mountains of these, all hard rock and metal... In my head, they are telling the story of my life, and then some.
Usually when I hear a word, it takes a little time before something starts playing in my head, It actually drives me insane. Then I need to find the artist and title, which is not always that easy. And I'm trying to keep it "lighter" around here, because a large part of my kind of music is not very musical.