What prissy, manual-of-style-snorting psycho with an OED up her butt made all these marks on my manuscript? With the exception of a few typos, those quote-unquote errors are in fact my quote-unquote writing style, dammit. Has the copyeditor ever heard of colloquial speech? If not, I'd be happy to introduce her to some choice examples. Just give me her phone number.
This is a common and understandable reaction to copyediting. It is not the correct reaction. But perhaps your editor, overburdened as she is with titles and bureaucratic hoo-ha, has forgotten to let you know what your response to the copyediting process is supposed to be.
When the copyeditor marks everything that could conceivably be called an error and questions the niggliest little things, she is doing her job.
She does this so that author and editor can be sure that any non-standard choices that were made in the writing of the manuscript were made deliberately, for the right reasons. Your role is to stet every instance in which the copyeditor thought maybe this might have been a mistake... but in fact you know it wasn't. Of course your role is also to ask yourself if occasionally your non-standard choices are getting in the way of your writing's clarity, and to agree to the changes to the actual mistakes that are inevitably in your manuscript somewhere.
In this way, you and your editor can go forward with publication in the sure and certain knowledge that when readers gripe about your bad grammar on page 57, or the egregious typo on page 104 (as they will, regardless of the perfection of your manuscript, trust me), it will be the complaining reader who has screwed up, not you. Isn't that reassuring knowledge? And it's because the copyeditor is such an obsessive-compulsive pain in the ass.
So when you get a manuscript back full of little red or blue marks and comments that you find persnickety and annoying, remember the peace of mind the copyeditor is offering you. You don't have to agree with everything she marks (even she may not). You just have to take a little time and check.