Perseverance is a golden trait for success and happiness.
85% of successful people are with average intelligence and high perseverance. Sports is the best teacher of perseverance. Marathon or long distance running is one such sport which can help you inculcate this important quality. Long distance running is a mind game. After few miles, when cheering of crowd subsides, it is the runner and his mind which is fighting the battle. Marathon training helps you win over this situation effectively.
I suggest people to remain active in sports forever to nurture such traits.
Keep miling, keep smiling :)