Well I'll jump straight back in then with the fantastic input of Tim Keller (Redeemer Presby New York) on our 'alienation from God' as humanity. Here goes:
"One way to understand our alienation from God is to consider the solar system. There is harmony between the planets because they all agree on the center - the sun. But if each planet were to have a different center for its orbit, there would be cataclysmic collisions. God's 'center' is His own glory; he does everything because it is consistent with his own righteous, holy perfect nature. We, however, 'center' on our own comfort and happiness; we live for our own glory. Therefore, there is an inevitable collision between God and man. Man is traumatized by and and is hostile to the holy presence of God. Yet we are built for fellowship with God. We cannot live with God and we cannot live without God. This is the essence of man's condition [without Christ; see Gen 3]."
Good stuff hey? Helpful way to explain it and think it all through.