From our Kinetix Tips series (email subscribers click through for photo):
Of course, I was operating with limited characters in that space, so one elaboration. A potential boss's comfort with that question really doesn't include him automatically saying "yes". The comfortable potential boss reflects on that question and compares the good and bad he/she brings to the table.
A quick "yes" to the question, "are you a good/best boss?", probably means they're not great at managing talent. Because it's way to hard to be that cocky about being good.