Rewriting is an odd exercise indeed. Reading your own work critically, analyzing it with an eye towards clarity, function, flow, story arc, imagery, etc. You’ll read a sentence and eventually it comes to you naturally–a better way of saying it. It’s difficult to attack a piece with all the elements of mind, or even to focus on one sole purpose while ignoring all the rest, and yet it can not be read as a flowing story, because if you allow that to happen, you’re either not paying attention to the details, or you are finished and have a polished work of art. Most likely, it is the former; you’re not paying attention and have gotten lazy.
Lowering your standards on your own written work is self-defeating, even while being a temporary high. “I’m good!” is necessary to continue the practice of writing. “I’m not good enough,” is necessary to produce a good story.