I've been editing things as long as I can remember.

One of my favorite books from second grade has a correction where a grammatical slip bothered me so much I was willing to WRITE in a BOOK in PEN. I loved grammar classes and was appalled my high school offered grammar only as an optional semester when it had been mandatory every semester at my middle school. My major in college was chosen when a friend pointed out English majors couldn't get jobs without graduate school*, but journalism included copy editors. When I applied to work at the campus newspaper, I pointed out they had spelled “sophomore" wrong on the application.

Out of college, I ended up with a job as a newspaper designer (not by preference, but because the industry is in upheaval) and yet was still editing: pointing out when a report referred to someone as the suspect's sister's girlfriend in one paragraph and his girlfriend's sister in the next, rewriting the caption on a picture of a donkey “rescued from a farm that neglected him this Christmas" (they neglected him every day; he was rescued on Christmas), and explaining the difference between “When they found him, he wrapped tape around his feet" and “When they found him, he had wrapped tape around his feet."  They moved me to an editing position as soon as continued upheaval opened one up.

And manuscripts! Another world of editing! It's not identical — a book is unlikely to mis-attribute the City Council votes; a newspaper is unlikely to  describe a physically-impossible sex scene — but there's still plenty  of overlap. All those mistakes in the above paragraph can certainly turn up in a manuscript, and I'm very good at finding them.

*Sorry, English majors, but at the time I only knew one English major; she was working at Dunkin' Donuts. And then there was that song from Avenue Q. The cards were stacked against you. Please forgive me. I still love you.