when someone is described as "shaking their head" to indicate a yes. its confusing, especially when there's no context added and its just "so-and-so shook their head" and you have to go back and figure it out. it really irks me because that's why we have the word nod- a shake is a no, a nod is a yes.
i fully understand it for people who english isn't their first language but I've seen friends who i know irl and know their first language is english and its still a mix-up. its not enough to fully put me off the fic, but its up there with defiantly and other mix ups. probably above them for me, because at least defiantly has most of the same letters and sounds as definitely. but bruh its something that is so weirdly irksome to me