Even by those who don't claim to be "Christian", this story is considered to be the greatest story that's been told. It is our story, the story of each of us; it is the gospel story. In his book The Cross and the Prodigal, Kenneth Bailey says this of the father in the story:
"Traditional Western interpretation has said that the father interrupted the son and didn't give him a chance to finish his speech. Rather, faced with the incredible event (of his father's stunning display of love by shamelessly running bare-legged towards him), he is flooded with the awareness that his real sin is not the lost money but rather the wounded heart.
The reality and the enormity of his sin and the resulting intensity of his father's suffering overwhelm him. In a flash of awareness he now knows that there is nothing he can do to make up for what he has done. His proposed offer to work as a servant now seems blasphemous. He is not interrupted. He changes his mind and accepts being found. In this manner he fulfills the definition of repentance that Jesus sets forth in the parable of the lost sheep. Like the lost sheep, the prodigal now accepts to be found."
What if God were really this good (with none of the qualifiers that we add)?? Think about it and be in wonder...