http://www.deviantart.com/download/123114743/id_ego_superego_by_conskeptical.jpg

This is a picture can be interpreted to represent the theory of the ego, superego, and id. You can see the two reflections in the marble representing the two sides of the human personality, the superego and the id. The id is the "wild child" in us, the devil on our shoulder telling us to seek self indulgence at any cost. The superego is the figurative angel on our shoulder telling us to seek perfection at any cost. the only difference between the devil and angel idea and the id and superego personalities so to speak, is that nether the superego nor the id are correct in their temptations. This is why we, in the sense of our personality and thought process, are the balance between the two. For human beings at least, ultimate indulgence is just as impossible as ultimate perfection.