Readers root for an active hero. They don't want to see the hero who doesn't want to be here and isn't going to help and is instead going to whine about every little thing that happens to him. They want to see Batman. Things don't happen to Batman. Batman happens to things.
However, as Joseph Campbell noted, most heroes will refuse the call to adventure. This may be because they have changed worlds unexpectedly and want to go home, or because they're naturally passive, or they don't feel like they're suited to being the Hero.
In these circumstances, it's tempting to simply make the hero be braver or smarter because you want them to be, but it's key to introduce change naturally. The character must willingly change, not because you force them to.
But how do you cause this change? I have a few ideas, one of which comes from The Hunger Games. I finally saw it this week, and while I'm not interested in getting involved in the child violence debate currently raging, I do want to talk about a moment that seemed significant to me. (Warning: spoilers ahead!)
Specifically, the moment when they announce that there can be two winners, not one, and Katniss whispers "Peeta." It's transformative for Katniss. She's been silently resisting the Games the entire time, unwilling to get involved more than necessary, waging a war of attrition by trying to stay out of the fight.
When she realized she could fight for Peeta instead of herself, she began to hope. That hope gave her the strength and courage to actively fight to win the Hunger Games, instead of hiding and running. Later, when the medicine heals Katniss and Peeta's wounds overnight, their fighting spirit is re-energized. No longer crippled, they feel that they can win this.
There is a storytelling lesson in that transformation. Katniss is the reluctant hero, but as the Head Gamemaker and any good writer knows, audiences want an active hero to cheer for. If your hero refuses to be forced to act, maybe they can be persuaded instead.
Hope. It is the only thing stronger than fear.
The moment of transformation from passive to active is crucial. It has the power to redouble your hero's faith in himself, and the audience's belief in him. It can cement his personality and give him something to fall back on in future times of trial. It cannot be overlooked.
What are some of your suggestions for getting a reluctant character to become dedicated to his cause?