The book I’m referencing was written in, IIRC, the 90’s or early 00’s. None of the ones that turned up in my search were it.

However, in case the one you’ve seen referenced was the one I mentioned, the premise I remember from reading it as a kid is basically that you should pay more attention to your subconscious. The bulk of what I recall is examples of people not doing that and discussion of how you can.

I do remember one specific thing from it. It describes the actions of a kangaroo before engaging in violence. It then specifies that that description is false, but you’ll never forget it. It’s true; I don’t remember why that came up in the book, but I’ve never forgotten the described actions.