This is a metaphor based on a method to catch nuisance monkeys. The monkey reaches in to get the fruit and holds on even though he is trapping himself. In relation to humans, he's in a bind. He is holding onto something, let's say a comfort zone for example, that is keeping him from bigger and better things in life. If he holds on, he's stuck, trapped. But letting go means losing the thing he prizes. So he can't make a decision either way even though to others the healthy choice is obvious. Often in life we can hold onto something meaningless in the grand scheme at the cost of something even more valuable. Like taking risks. "Better to have loved and lost than to never have loved at all". Many will never find love because the fear of abandonment is too great. Sorry if this rambled.