People dismissed the XP book by saying it was just stating practices that already existed. Articulating and selling an idea is a huge part of the challenge. Fifteen years later if you're having any success at all with Scrum it was because your team adopted the half of XP that didn't outright disagree with Scrum.

I liked the Refactoring book because it gave me names for things I figured out in 1996 (unfortunately while using VI as an editor, gave myself RSI in the process). It was part of an education in the value of books that help you only by existing so you can hand them to people who ask a lot of questions.

I had a boss who was big in the Kanban 'movement'. We got along famously, in part because I re-invented a Kanban board in 1994 when faced with a convenient whiteboard for the first time.

You can do a lot of amazing things with decent first principles. You can make some amazingly large messes without them.