Staying interesting depends on being allowed to be bad at something. Once a person is fixed in the role of the one who knows, every new thing costs them status to attempt, so they stop, and the range slowly narrows to what they can already do well. Permission to be a beginner is not a courtesy; it is the condition for anyone continuing to grow.

Take up something you are plainly unqualified for, and let people see you doing it badly. And where you have authority over someone, make it obviously safe for them to be new at something in front of you.