When it comes to fictional universes that are set in outer space, I like it when most of space is left uncharted and mysterious; it makes the universe feel immense, that just about anything can be found if one only travels far enough beyond the horizon.

But when most of that space has been charted, explored, and colonized, it makes the universe feel small and too familiar; it makes it so that it feels like everything worth discovering has been discovered, that there is nothing of any great importance left to find.