How do you learn interesting stuff like this? Do you just sit back and read it with interest, or do you take some kind of notes?

I always found taking notes to be pointless, especially when you have a textbook or pp slides to reference. You're just copying something and hurting your hand for no reason, and it takes so long that I focus on the notes more than the material.

Everyone in class basically copies the material onto their notebook though. I think it's a virtue signalling thing. It makes them look like a "good student" whereas it looks weird to just sit back and watch the lecture as if it's a movie.