This is an IMAGINARY STORY... aren't they all?

Whatever Happened to the Man of Tomorrow?
Alan Moore: Writer - Curt Swan & George Pérez: Artists.

From Whatever Happened to the Man of Tomorrow? (DC Comics, 1986) opening page.

This is an IMAGINARY STORY (which may never happen, but then again may) about a perfect man who came from the sky and did only good. It tells of his twilight, when the great battles were over and the great miracles long since performed; of how his enemies conspired against him and of that final war in the snowblind wastes beneath the Northern Lights; of the women he loved and of the choice he made between them; of how he broke his most sacred oath, and how finally all the things he had were taken from him save one. It ends with a wink. It begins in a quiet midwestern town, one summer afternoon in the quiet midwestern future. Away in the big city, people still sometimes glance up hopefully from the sidewalks, glimpsing a distant speck in the sky... but no: it's only a bird, only a plane — Superman died ten years ago. This is an IMAGINARY STORY... 
Aren't they all?