One of the purposes of a great story, is to show that one has control over ones own destiny.
The choices the character makes, especially in the midst of despair, and disorder, shapes his or her live within the story. Harry Potter could have chosen to stay at his uncle’s house. Wolverine could have chosen to accept the fate of all mutants eradicated. The Avengers could have chosen to continue to fight each other, leaving the world to deal with the destruction of a force, no one else but them could defeat.
Instead these characters, as many others, took fate into their own hands. They chose to rise up against an enemy, or against the odds, or against their own fears. But they did take charge, and the results of the story is different because of it.
The story of our lives in no different in that respect. What we choose to do in the moments of despair, or the moments of joy, shapes our destiny, sometimes dramatically. Like any good story, our own story is made out of overcoming stumbling blocks, many of which are our own making. Those moments make us stronger, they make us the hero of our own book.