When we are little, we master our physical self. Witness the toddler who can't seem to stop smearing his sleeves with food. When we grow older, we master our emotional self. Witness the young adult who goes in and out of relationships. Witness the husband and wife who quarrels over little things every day. When we are old, most of us (hopefully) would have discovered our true "self". We have achieved mastery of our inner nature. Then it is time for us to leave the world. Ain't life a bitch?