All writers should go read every word of this essay by Maria Bustillos, written on the occasion of editor Carrie Frye’s departure from the Awl.
The gist of it: your editor is your friend, not some censorious know-it-all trying to ruin your work. (Well, usually.) One of many perfect passages:
…at its best there is no hostility, and no jockeying for an advantage in this symbiosis: no ego, no performance, just an intent shared focus on making something good together for the reader’s benefit. A finished piece of writing made in this way will transmit a certain quality often called “polish,” but which might more accurately be described as “camaraderie.”