Fear, it is the biggest “emotion” humans and animals feel.  Fear can drive you to do many things you couldn’t before or it can freeze you in your steps.  It all depends on how you handle it.  Fear is necessary to become stronger.  It is arguable that you can be weak from it, frozen up, but fear can drive you to do things that you never thought you could as stated by The Blind Prisoner from “The Dark Knight Rises”

“Blind Prisoner: You do not fear death. You think this makes you strong. It makes you weak.
Bruce Wayne: Why?
Blind Prisoner: How can you move faster than possible, fight longer than possible without the most powerful impulse of the spirit: the fear of death.
Bruce Wayne: I do fear death. I fear dying in here, while my city burns, and there’s no one there to save it.
Blind Prisoner: Then make the climb.
Bruce Wayne: How?
Blind Prisoner: As the child did. Without the rope. Then fear will find you again.”

Blind Prisoner:…