A bad early boss teaches you exactly who you refuse to become when you’re the one in charge.

Being badly managed is unpleasant and oddly instructive. You experience the specific effects of particular behaviour from the receiving end, which is a view nobody has of their own conduct. Vague ideas about being a good leader are useless; a concrete memory of how it felt when someone took credit or blamed you in front of others is not. That memory is a more reliable guide than any advice.

Note two things this person does that you will not do, in plain language rather than principles. Not respect people, but something like never correct someone publicly. Keep the note somewhere.