@lunalein@bookstodon Any Too Stupid To Live protagonists. Even more so if they don't know basic facts about something they're supposed to be an expert in.
Similarly, authors who set the expectation they've created only a slightly altered version of the world as we know it, but who throw out large swaths of well-known history to achieve that. It's okay to create an alternative timeline!
Last one: historicals which describe ahistorical clothing at great length.