I have just been reading the first ten verses of Luke fifteen - the parables of the lost sheep and the lost coin. Losing things is always a pain and we all have our different techniques of trying to find them. I guess the joy of the finding is usually somewhat in proportion to the impact of the losing. The value of what was lost may also influence how much we celebrate. These two stories are designed to remind us how important we are to God. We matter - and what a great thought that is!
I have been reading Henry Wansbrough's little commentary on the passage (BRF, 1998) in which he comments: "But the point of the two stories is precisely to show that the joy in heaven cannot be calculated according to any scale of reason."
The overwhelming reaction of these two finders is a pointer to the abundance and generosity of the love of God.