When I was in my early 30th and was teaching one part of Sacks- "Mind's Eye" book in a college writing class, I realized as I was reading for the first time that people can actually see stuff in their head. I thought when people say "picture this" or "visualize it" it was all metaphorical. All I see is black. I just know it without actually seeing it. Turns out I have aphantasia and it is pretty rare. But it blew my mind. Just the variety of human experience. I don't like all his books but I usually get enough interesting insight. His autobiography was pretty good too. His books on music and hallucinations were pretty interesting to me.