The first human who hurled an insult instead of a stone was the founder of civilization.
Sigmund FreudLet 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 FreudIn mourning it is the world which has become poor and empty; in melancholia it is the ego itself.
Sigmund Freud