When Dave was a toddler, I would sometimes tell him stories at bedtime.  It was a good way to get him to settle down: no lights on, like you need for reading.

I don't remember many of those stories. There was a series about Bob (because he bobbed on the water) the (magic) golden sailboat and David and their ocean and harbor adventures. There was a whale with a deep slow voice and a hyperactive dolphin named Joy and a storm or two. About when the underwater city with its underwater inhabitants came around, the story sort of petered out.

One night, I couldn't come up with a story. No main character, no plot, no moral - I just drew a blank. But at that age, Dave was mad about trains, and it was winter. So I talked about the little trains and trolley cars that just went back and forth all through the storm, clearing the tracks inches at a time. And then about the train plows that come through after the storm, with their pointy noses sending up great wings of snow on either side, glinting and glowing in the sun, as they power down the long overland stretches of rail.

It was description, not story. It had a tiny lesson about getting things done by a big-bang approach, or by taking it little by little, but no judgment about which is better.  Did that even qualify as a "story"?  I didn't think so at the time; I rather thought I had wimped out that night.  But not Dave! To my surprise, he requested that story again and again, and remembers it still.