Every normal person, in fact, is only normal on the average. His ego approximates to that of the psychotic in some part or other and to a greater or lesser extent.

Analysis Terminable and Interminable, sect. 5 (1937); reprinted in Complete Works, Standard Edition, vol. 23 (ed. James Strachey and Anna Freud. 1964); as quoted in The New Penguin Dictionary of Modern Quotations by Robert Andrews, Penguin Books, 2001.