Let us consider the polarity of love and hate.... Now, clinical observation shows not only that love is with unexpected regularityaccompanied by hate (ambivalence), and not only that in human relationships hate is frequently a forerunner of love, but also that in many circumstances hate changes into love and love into hate.
Sigmund FreudOne feels inclined to say that the intention that man should be 'happy' is not included in the plan of Creation.' . . . We are so made that we can derive intense enjoyment only from a contrast and very little from a state of things.
Sigmund FreudWe should picture the instrument that carries our mental functioning as resembling a compound microscope or photographic apparatus.
Sigmund Freud