As the writer, you're always a presence in the song. If you get close to what human beings are like, you're writing about common experience. We all do much the same things, so if you nail somebody, then you've also nailed yourself.
Writers often feel as if they exist on the periphery of life. By being observers, we feel a bit detached from the actions of the moment. It's difficult to blend in, to become a part of things.