It is easy to see that the ego is that part of the id which has been modified by the direct influence of the external world.
Sigmund FreudThe behavior of a human being in sexual matters is often a prototype for the whole of his other modes of reaction in life.
Sigmund FreudWe find a place for what we lose. Although we know that after such a loss the acute stage of mourning will subside, we also know that we shall remain inconsolable and will never find a substitute. No matter what may fill the gap, even if it be filled completely, it nevertheless remains something else.
Sigmund Freud