Creative writers sometimes mangle grammar on purpose or get creative with punctuation. At the drafting stage, we keep a dictionary and style manual at hand. When slips are unintended, we count on our copyeditors to catch them.
But at some point, most of us get advice on punctuation or grammar from a friend, relative, or strangers on social media. Sometimes friends or beta readers read our draft and point out what they believe to be errors.
The problem is, they’re often wrong.