The more you are stronger mentally, the more the tasks that appear easy to you. Do not judge anyone's effort by the way they do things easily or effortlessly. While coming to a judgement about anyone's efforts, take their mental strength into consideration.
Ignoring the metal toughness and judging people, only by the efforts that they put in or by the extra hours they spend, encourages everyone to show off and eventually make them fake in front of the person who judges them!
Mental strength includes the determination, fearlessness, strong belief and self-confidence etc aspects. Certain people develop them naturally over a period of time! Not having these is not anyone's mistake but a limitation. And not trying to improve upon these is a definite mistake, I think!