The proliferation of infomercials is a good example. Sales people know we are more apt to buy a product if we hear stories of others that bought the product and were happy. Their stories moved us to action. Whether we're as pleased as those who appear on the commercial is another matter. But it was the story of someone else's happiness that moved us to action.
Sad stories can have the same effect.
We hear of children starving in a far away country or of a family suffering in our own neighborhood and we're moved by our emotions to act on their behalf. There's something in their story that we identify with, that moves us to compassion, and finally to action. Stories can also bring a form of immortality to people. As long as someone's story is remembered they are never really gone from us. Families spin tales about long gone ancestors and their accomplishments to perpetuate family traditions based on that person's life story.