Notes about how you really think or feel? Stakeholder (secret) analysis)? Things you heard or saw that you want to keep a record of, just in case? Anything can go into a little black book...that you don't want others to read. Saving Changes...
I joke a lot with some of my teams saying that I have a black list....but I never did it. I try to be very transparent at least regarding team members and stakeholders Saving Changes...
Lol, Sante, I have a small blue notebook, and it fits in my pocket, usually, I use pencil, so it fades with days. My daughter always laugh about it, and she calls it the secret book of Baba