Context matters and notice that Luke 15 begins with tax collectors and sinners coming to Jesus and the Pharisees and scribes grumbling about it. This is the only place in the Gospel where Jesus tells three consecutive parables to make the same point (the lost matter to God). There are three parables of things lost and found: There is the lost sheep (one of ninety-nine) which the shepherd searches and finds; there is the lost coin (one of ten) that the woman searches and finds; and, finally, there is the lost son (one of two) for whom the father waits and who eventually returns. Three parables one point: God cares for those who are lost and desires them to be home.
The items get lost in different ways: the sheep just wanders off -- looking for greener grass? Got scared by a puff of wind? Either way the sheep is lost and the Shepherd has to leave the 99 and go and search until it is either found or evidence of its demise is found. The coin has no self determination or self awareness. It is just lost. It has inherent value to the woman who is looking but had no choice in the matter of being lost or found. It was lost, the woman found it (after searching diligently).
The lost son chooses to disrespect his father and get lost. The story of the lost son holds the context in perfect balance. There is the younger son (the tax collector/sinner) and there is the elder son (the Pharisee/scribe) and in the middle is a loving and gracious father. The attitudes of the two sons are intended to be reflections of the attitudes of the two groups around Jesus with the loving invitation of the father between them. Both sons are outside the will of the father, the younger son because he is disobedient and the elder son because he is obedient for the wrong reasons. The key for us is whether we have wondered off and squandered our living or we have stayed home and been "good little boys and girls" God's love for us is unchanged and constant and transformation. All we need do is fall into the embrace of the father to begin again.