Bob Plitt has seen things that would chill the blood of most men. He is on the front lines of a never-ending battle against the forces of evil. Where others fear to tread, Bob Plitt plunges bravely ahead. Bob Plitt is a plumber. And as a member of that noble profession, he was not at all happy to read my throw-away line a week or so back about “plumber’s crack,” that exposed cleft that is often the, um, butt of jokes.