Greed is a bottomless pit which exhausts the person in an endless effort to satisfy the need without ever reaching satisfaction.
Is love an art? Then it requires knowledge and effort.
We may know ourselves, and yet even with all the efforts we make, we do not know ourselves. We know our fellowman, and yet we do not know him, because we are not a thing, and our fellowman is not a thing. The further we reach into the depths of our being, on someone else's being, the more the goal of knowledge eludes us.