While advancing in our lives, we move like earthworms.
With great difficulty, we stretch and reach out to where we want to go, then pull our rear-end (again with great difficulty) to settle down in our new position. This motion is repeated several times until we reach a completely foreign land and settle down there for a while before we start wondering "Where the heck have I reached?".
That's when we start thinking about the land we left behind and realize that even though we managed to pull our body off, we left something behind – our hearts.