What happens in the paradoxical case is merely that the place of the external frustration is taken by an internal one. The sufferer does not permit himself happiness: the internal frustration commands him to cling to the external one. But why? Because – so runs the answer in a number of cases – one cannot expect Fate to grant one anything so good. In fact, another instance of “too good to be true”, the expression of a pessimism of which a large portion seems to find a home in many of us. In another set of cases, just as in those who are wrecked by success, we find a sense of guilt or inferiority, which can be translated: “I’m not worthy of such happiness, I don’t deserve it.” But these two motives are essentially the same, for one is only a projection of the other. For, as has long been known, the Fate which we expect to treat us so badly is a materialisation of our conscience, of the severe super-ego within us, itself a residue of the punitive agency of our childhood.
Sigmund Freud, letter to Romain Rolland "A Disturbance of Memory on the Acropolis"