Because there's really two different "wants". We "want" to be productive but we "want" to screw around all day browsing the web/playing video games. The former

Because there's really two different "wants". We "want" to be productive but we "want" to screw around all day browsing the web/playing video games. The former requires focus, effort and discipline while the latter requires none. How rewarding they are is commensurate with the amount of effort.