Sometimes when I write a paragraph which I think is bloody good, I pause and realize there's nothing I could add further to the text. I'm momentarily stuck. How to keep repeating brilliance? Then I stop to think and see that brilliance is a bad term, that I'm overrating myself. There's something more to be said, there's a word that was badly chosen, the phrasing could be better. So I end up rewriting the whole paragraph, and add another to complement the first one.
This way, I quickly write an entire text when it seemed impossible to move on.
My tip: always know what you want to write about. Always have a clear plan for the story you want to tell. This way, you'll only be able to abandon the story when it's finished.