Based on the justly celebrated 1974 nonfiction by Studs Terkel, the musical Working is a two-act series of vignettes on the joys and frustrations of professional life, and the search for satisfaction in even the most mundane of careers. It's somewhat ironic, then, that in the Timber Lake Playhouse's current, wholly engaging, superbly performed production of the show, the most effective segment in it concerns a man who actually doesn't work for a living.