From Jung’s The Undiscovered Self

Two passages that really stood out

When a neurosis breaks out in an adult, the fantasy world of childhood reappears, and one is tempted to explain the onset of neurosis causally, as due to the presence of infantile fantasies. But that does not explain why the fantasies did not develop any pathological effects during the interim period. These effects develop only when the individual comes up against a situation which they cannot overcome by conscious means. The resultant standstill in the development of personality opens a sluice gate for infantile fantasies, which, of course, are latent in everybody, but do not display any activity so long as the conscious personality can continue on it’s way unimpeded. When fantasies reach a certain level of intensity, they begin to break through in to consciousness and create a conflict situation that becomes perceptible to the individual, splitting them in to two personalities with different characters. The dissociation, however, had been prepared long before in the unconscious, when the energy flowing off from consciousness (because unused) strengthened the negative qualities of the unconscious personality, and particularly it’s infantile traits.

Since the normal fantasies of a child are nothing other, at bottom, than the imagination born of the instinctive impulses, and may thus be regarded as preliminary exercises in the use of future conscious activities, it follows that the fantasies of the neurotic, even though pathologically altered and perhaps perverted by the regression of energy, contain a core of normal instinct, the hallmark of which is adaptedness. A neurotic illness always implies an unadapted alteration and distortion of normal dynamisms and of the imagination proper to them.. Instincts, however, are highly conservative and of extreme antiquity as regards both their dynamism and their form. Their form, when represented to the mind, appears as an image which expresses the nature of instinctive impulse visually and concretely, like a picture.

Recognition of the shadow, leads to the modesty we need in order to acknowledge imperfection. And it is just this conscious recognition and consideration that are needed wherever a human relationship is to be established. A human relationship is not based upon differentiation and perfection, for these only emphasise the differences and call forth the exact opposite; it is based, rather, on imperfection, on what is weak, helpless and in need of support – the very ground and motive for dependence. The perfect has no need of the other, but weakness has, for it seeks support and does not confront it’s partner with anything that might force him in to an inferior position and even humiliate him. This humiliation may happen only too easily where idealism plays to prominent a role.