I took this class without a prerequisite, so I needed the professor’s permission. I called him, and he opened with “tell me why I should let you in my class.” After a half hour of grilling me on my life and study habits, and telling me about how supposedly strict the class would be, he decided I was serious and not just looking to skip the prereqs, and let me in. It didn’t take long for him to become my favorite professor (and later, my graduate advisor).
The man must be damn near twice my age. I wish I had half his energy.