Vonnegut does this a lot too - toying with an idea over and over again until he feels it is fully explored.
Ironically, the first time I remember being struck by an opening line was from Something Wicked This Way Comes by Ray Bradbury:
"The seller of lightning-rods arrived just ahead of the storm."
It's almost too forward — but I loved the visual. It's hard to not be hooked by the impending storm.
You can do a lot of these small "demos" or short stories and save them for a future novel. Or instead write them together and make an anthology, like the Poe stories.
We need more anthologies.