In the 1970s, an Appendix Quarter Horse stallion by the name of Impressive rose to prominence as a show horse and sire. I'm no big fan of the breed, but even I can admit that this horsed filled the eye. Impressive was, in a word, impressive.
Unfortunately, the stud had a genetic flaw that no one could prove until 1992, when researchers isolated the mutated gene as pertaining to horses with pedigrees that traced back to Impressive: hyperkalemic periodic paralysis or HYPP. Affected horses demonstrated a sensitivity to potassium.
So, what does this have to do with writing?
This grossly influential sire was impressive, but innately flawed. What the stock industry saw as the perfect representation of a Quarter Horse wasn't. In over fifty years, I have yet to come across any example of writing that could be described as perfect. Impressive, yes.
Everything written has some weakness, some flaw. Writing may hit heights of excellence that impress readers and confer accolades upon writers, but never is any document perfect. This crucial distinction matters in ghostwriting and editing.
Especially in longer documents, no editor catches every single error. After all, an editor is human with personal preferences and unique insights. One might favor serial commas, another might not. One may enjoy exposition, another may not. Differences range from subtle to blatant and affect the manuscript in different ways. Also, being human, editors miss things. Therein lies an important reason for the editor returning a "marked-up" manuscript rather than a ready-to-publish document. The writer has the obligation to review the editor's recommended changes and suggestions for improvement and then to accept, decline, and revise accordingly. The editor should not revise, because no one writes in that author's voice better than the author.
The upshot: writer and editor can tweak a document into infinity in the futile pursuit of perfection. Perfection eludes us because we're not perfect. We can and should, however, strive for excellence, and that requires a whole host of skills that come into play when transferring the thoughts in our minds to arranging words in sentences that others can comprehend and appreciate with little distraction.
Think of it this way, though, those small flaws give our writing character. They contribute to our voice. Like the people who write it, content comes alive with personality when quirks and preferences and character flavor it.
Aim for impressive, not perfect.