New and beginning authors often (loudly) assert their ability to edit their own work. If you are “editing” your own manuscript, you have a fool for a client. There is no such thing as self-editing—the best you can do is make revisions and admire your work. For that reason, we need other eyes on our work.
As authors, we see what we intended to write rather than what was written. We misread clumsy sentences and overlook words that are missing or are included twice in a row. If you are in a critique group, you have a great resource in your fellow authors—they will spot things you have overlooked your work just as you do in theirs.
The first draft of any manuscript is the story as it flowed out of your mind and onto the paper. Yes, there is life and energy in your words, but your manuscript is not publishable at this stage, no matter how many times you go over it.