You see it when we meet the hero of the movie for the first time, and the hero does something nice, like save a cat, that makes us like him and want to go on the journey with him.

So that you're not just handed something that's entirely new to you with no idea which direction to go, we actually do set you off on an appropriate path.

Many people in similarly desperate circumstances give in or go mad. Something the survivors do with their thoughts helps them find the guts to carry on in spite of overwhelming odds.