I have never, and will never, annotate books. There are a few booktubers who I either watch, or have watched in the past, who annotate them to an extreme and I find it quite horrifying to watch. They highlight passages, underline sentences, write comments in the margins and although I am very much a case of ‘each to their own’ and ‘you do you’ I could never actually do it myself. It seems sacrilegious to me.
In my opinion this is a much more acceptable way of doing it.