For a creative person, what could be is as tangible, if not more real than what is. A piece of music is not simply what it is but is a collection of moments of possibility. In each moment what happens next appears as both what actually happens and what could have happened. This is what makes music alive.
A painting is full of choices. The best paintings are the ones where the “could have beens” have been paired away until what is left is what seems to be the only right choice. Without the possibilities that weren’t right being noticeably absent, those paintings wouldn’t be as good.
Songs that are overloaded with ideas/notes quickly become monotonous. Songs that have an economy of ideas leave space for imagination and so are more engaging.
And yet, what is more fascinating than music or any other art that seems complete exactly the way it is?