Luke 15: 1-10 Maybe the sheep called "lost" did not feel it fit into the herd mentality. Maybe it was not so concerned about security and safety, but rather wanted to go off and explore. I believe that the shepherd saw great value in having this sheep. The shepherd found the sheep but did not kill it or break its leg to keep it from running away again. The shepherd wanted to celebrate having found the sheep.
Being lost is a designation that is often given by the herd to one who is no longer around. I wonder if the sheep who had gone off would have seem itself as"lost"? Trying to live outside the box can be risky business, but maybe more risky for the herd than for the seeker, who at times is called "lost" by those who want to remain in the status quo. I wonder if Jesus was thought to be "lost" by other religious leaders and congregations? He said, "The kingdom is in your midst," but then you still have to search for it. When you search, that is when you are found...by the Good Shepherd.