7. Schedule/Workload
There was a remark made during last week's Smackdown, where John Cena was called a "part-timer," during an in-ring promo by Dean Ambrose. With all due respect to the Lunatic Fringe, John Cena is far from a part-timer. Not only is Cena on nearly every televised show, which now he's exclusive to Smackdown, but he is always on the job, but more often than not, you can find John Cena and most house shows as well, barring any sort of injury that would prevent him from appearing.
But, my point is, no one should ever question whether or not Cena has ever carried his workload. Not only that but in between WWE events and appearances, Cena can be found on a movie set, filming a commercial, speaking at an engagement or somewhere....working.