I like to do these things on the piano that I call vomit improvisations. They reject the concept of time and chronology in music. For the first 30 seconds or so I let negative emotions flow through me and the music will sound ugly or disjointed as a result. But then I shift my emotions to self-surrender and it transforms the musical atmosphere so that it facilitates explosions of beauty that would've otherwise never been possible without the ugliness in the beginning. The cool part is that if you then listen to the song again, the ugly beginning will retroactively sound pretty, since the improvisation has already been digested. Like reverse vomit!