Have the words fallen, or are they still in the process of coalescing on the page?
This could be the carelessly-written tale: the story that falls apart in your lap*, completely devoid of structure and theme. Maybe it’s a truly irritating story, and the little imps are in fact beginning to swarm at the reader, like a plague of literary ants. Or maybe this is what happens if you dawdle when reading: the words get bored with your dilly-dallying, and go off in search of a more captive audience. Maybe the tale itself is so dull that the words have given up trying to sound interesting, and are heading off for tea and/or a new place to hang out (preferably a fresh grid-lined Moleskine, or maybe one of these pretty hand-printed ones by shoofly). Contrariwise, maybe those little letters are coming to life and jumping off the page, so animated is the tale they tell.
This could be one of those exciting, unpredictable stories, where the next sentence only comes into being a split-second before you read it, until which time the words just sort of mull about at the bottom of the page, waiting to form the next line. It might also be a sly strategy to stop the overly-keen flipping to the back page to find out the ending: if the words aren’t there yet, what’s the point? Have patience, young grasshopper!
* Have you ever tried to read a cheap, glue-bound paperback while lying on your back under a summer sun, using the flimsy pages as a face-sized sunshade? The result is truly Yeatsian: “Things fall apart, the centre cannot hold”. Pages everywhere. Glue/wax doesn’t hold up under solar heating. Just ask Icarus.