Of the many powers possessed by Superman, there's only one that has helped make the hero the beloved figure he is. Forget x-ray vision, super strength or freeze breath because the Man of Steel's greatest, and least known, power is a lot more useful than any of them.
Superman is perhaps the most iconic hero of all time. Of the many superheroes that debuted during the Golden Age of Comics, few have been able to cling onto relevancy in the same way that the last son of Krypton has. In many ways, he's helped set the bar for heroes, with Superman's classic costume being nearly as iconic as he is. Clark Kent is more than just a man who can shed his suit, jacket and tie and become a hero capable of Herculean miracles. He's someone who has helped define what it means to be a superhero for the comic book medium.
But what is it about Superman that has helped him become one of the paragons of the DC Universe? Apparently, the best answer for that lies with his adoptive earth father, Jonathan Kent. In Action Comics #867, the menace known as Brainiac has made himself known to Superman. After he talks it over with his cousin Supergirl, Superman realizes he must go into space and confront the villain directly. But before he can do that, he has dinner in Smallville with his Ma and Pa and lets them know the danger he's about to get in. Afterwards, Clark has a heart to heart with his dad where he asks him if he's worried. Pa Kent tells his boy he no longer worries and expresses his confidence in his son by telling him his greatest power is "knowing what the right thing to do is."
Ever the humble one, Clark tries to credit Jonathan for his “power.” But Pa Kent tells Superman that he got it from a number of people. It's hard to deny that what Jonathan is saying is true, as Superman has always had a strong moral center that's guided him in his career as a hero. By bringing up Clark’s most noble trait, Pa Kent has discovered what's given Superman his staying power as a heroic icon. It’s not just that Superman is an important figure in his own universe, he’s one of the most iconic superheroes in the real world as well. He’s regarded as the gold standard for heroism, and DC has no doubts about Superman’s popularity. But Jonathan puts into words just why Clark's stardom has risen so high.
Superman is man of unwavering principle—an everlasting beacon of goodness in a world where that's sometimes hard to find. He resonates with fans who desire heroes devoid of cynicism or irony. At his core, Clark is just an average guy who does the right thing because he listens to his heart. It may not stop alien dictators or magical demons, but Superman's best power has kept him a beloved icon for decades.