The best answer isn't always yes.
Sometimes it is good to be challenged.
A challenge isn't always an attack--even an aggressive challenge need not be an attack. Sometimes the challenger is trying to support you.
"Yes" is a supportive answer. It builds confidence; it feels good.
But, obviously, it's not always an answer that is appropriate.
Sometimes a writer has to hear "no". No, this isn't working; no, your ideas are not getting across; no, this is not a masterpiece, it is still a mess. It doesn't feel good to hear no.
But if you're working with an editor, you should be open to hearing what lies behind their "no". If you're working with an editor, chances are that editor wants to get your work accepted almost as much as you do. After all, an editor's reason for being is to make something read well and be accepted by the chosen audience. If an editor is working on your piece, then behind every "no" is a "yes"--yes, I want you to succeed; yes, I want your ideas to be presented in the best way; yes, I want this piece of writing to be accepted.
One problem I face working as an editor is that often my "yes" is taken for a "no." I suggest changes in order to strengthen the work, because I see how the work could be improved. I say "yes, this good idea can be presented even more effectively." But that yes is too often taken for a "no, your work is no good."
Just remember: any editor is interested in putting out work that will be accepted--from the editor-in-chief of a newspaper and the top editorial staff at publishing houses, to all the other editors, copy-editors and proofreaders out there. The point of editing is to produce work that is well received. What you hear as a "no" may well be a "yes, I want to get this work accepted by its intended audience."
As a freelance editor, there is no other measure of success of my work: did my client's work get accepted by their professor or the journal or publisher to whom they were submitting? All my efforts are aimed at working on how to improve the work at hand.
I suppose I write this out of a sense that I would like to be able to tell clients that there are problems with their work--not because I'm trying to find fault, but because I'm trying to find a way to succeed--without having them act as if the world ended.