It starts perhaps with a single sentence, or a word even, running through your head. You get it down into visible form and it looks great. You're running on pure creative excitement at this point, fashioning prose and poetry so quickly that you can hardly be bothered to think of anything other than emptying the imagination onto a physical space, releasing you from the burden of it.
At last, you run out of steam. You stop to breathe, to crack your knuckles, to grab a swig of drink or to take a bite of long gone-cold food. It is then, as you look back at what has been transcribed, that you realize that something has been tragically lost in the translation from inspiration to the written word. Still recognizable are the little gems of phrases and lines, remnants of that original lighting bolt that sent your writer hands into their fury. But the vast majority of the language surrounding these spots of brightness fall dead and flat on the page or screen. On your lips, the words taste wrong, gritty, as if the batter composing the work had not been properly mixed into a homogenous liquid.
And sadly, try as you might, you are unable to fix the numerous structural and conceptual deficiencies. You realize that this work was built on a faulty, flawed foundation. Even complete demolition and a rebuilding process would most likely fail to make good on your once-glorious vision, as the original drive that pushed you in the direction of its creation has, by this point, all but fizzled out.
It is forever doomed to lie as unfinished, abandoned work.