And [Robert Trivers] said, do not accept a job in which you are not exposed to undergraduates because teaching undergraduates means exposing yourself and the thinking that you are presenting to naive minds who will throw curve balls at you. And some of those curve balls are going to be nuisances, and maybe they'll waste your time, but some of them are likely to reveal to you the frailty in your own thinking or in the thinking of the field, and that is the way that progress is made.