Harris is describing something counterintuitive about human nature: we treat rest as a luxury reward rather than a necessary maintenance tool, like waiting to oil a machine only after it seizes. The busier you actually are, the more you need those small pauses—a fifteen-minute walk, five minutes staring out a window—yet these are precisely the moments we eliminate first, convincing ourselves there will be time later. A surgeon working a sixteen-hour shift who takes a lunch break isn't losing productivity; she's preventing the exhaustion that makes her hands unsteady. The paradox Harris points out is that we've got the timing backwards: relaxation isn't something to earn through completion, but rather fuel for the engine while it's running hardest.