Let's take a look at the stories as a whole. What seems to be the main themes?
The first thing that strikes me is the aggressiveness of God in pursuing failing humanity, regardless of humanity's condition or how they got into that condition.
The second thing this leads me to consider is how pitiful is our own righteousness. And, how humble I need to be about pride in living to any set of rules. I don't think I can out-Pharisee the Pharisees in keeping rules and Christ's stories are pointed right at the Pharisees.
Lastly, (well I sure there are lots more good points to glean that just these three), is the theme of celebration by God when someone turns to Him.
Tell me, what do you get out of these stories? I'd love to hear!