Long ago, before I knew much of anything, I tried writing a short story where each character was unnamed. I called them things like "Mr. X" and "Young S" - thinking they would reveal their names and personalities and history as I went along. This didn't work at all.
In fact, precisely the opposite: I couldn't "go along" writing without having met the characters. Once I realized this, I started over and took the time to build up the people beforehand.
Of course anyone who has written very much will recognize this as a "Duh!" realization. But in my naive charioteering I had put the cart before the horse.
I just caught myself doing this same thing again just now in another story. But in this case the character I was leaving unnamed was an entire civilization and star system. Finally, with a sense of déjà vu, I realized why I couldn't continue.
So now I have a star these people come from - a binary star near Sol. And as a bonus I've taken the opportunity to invent an entirely new way a civilization might arise in such a place. The people of this civilization are coalescing out of the mists of my imagination and I can now proceed.
I suppose I'm a proper idiot for having to learn this lesson twice when most writers, using some writerly instinct that I lack, would never gone this way in the first place.