Horace on Editing

If you read anything aloud to Quintilius, he'd say "pray change that, and that". You would say you couldn't do better, though you'd tried two or three times, to no purpose. Then he'd tell you to scratch it out and put the badly turned lines back on the anvil. If you preferred defending your error to amending it, he wasted no more words or trouble on preventing you from loving yourself and your handiwork without competition. A wise and good man will censure flabby lines, reprehend harsh ones, put a black line with a stroke of the pen beside unpolished ones, prune pretentious ornaments, force you to shed light on obscurities, convict you of ambiguity, mark down what must be changed. . . . He won't say, "Why should I offend a friend in trifles?" These trifles lead to serious troubles, if once you are ridiculed and get a bad reception.

— Horace, Ars Poetica (trans. D. A. Russell)