Defined by Fate

With all of these superhero movies coming out, it got me a thinking: what determines if a person becomes a superhero vs a supervillain? Is it a choice or is it decided by circumstance?

For example: Say this dude eats some tainted meat, but not just any tainted meat, tainted organ meat (say in a steak and kidney pie gone bad). Now he has a super power! What power, you might ask? I'll give you a hint: his is called The Organ Grinder. Yep, he has the power to turn anyone's organs into ground mush just by thinking about them. Could this person every be a Super Hero, or no matter how good or moral he is at the core, would he become a Super Villain? How could he uphold justice with this power? "Stop, thief! ...or you will regret it!" "I've just Ground your left kidney, it is not to late to turn back, thereby saving your right one from a similar fate!"

Another example: A man goes in for some therapy, but unbeknownst to him, his therapist is an alien mindbender. He imparts an ability to his patient by accident: anyone he touches becomes self actualized. Since he was going to a therapist, he was obviously evil to the core, but was trying to learn to suppress these urges. Now that he has Power, could he become true to himself and become a Super Villain? With that specific Power? "Now my Master Plan is in place! Soon, I will rule the world, right before I destroy it! All by the use of my Super Power of making people feel truly alive! Bwah-ha-ha-ha!"

The ability to make people's heads explode? The power to destroy the frontal lobe of anyone whose hand he shakes? Can change any one thing in the Universe, but a random person dies every time he uses his power? Can any these people become daring do-gooders or are they defined by their abilities?

The Edward