Just as we tend to assume that the world is as we see it, we naïvely suppose that people are as we imagine them to be. . . .
All the contents of our unconscious are constantly being projected into our surroundings, and it is only by recognizing certain properties of the objects as projections or imagos that we are able to distinguish them from the real properties of the objects. . .
Cum grano salis, we always see our own unavowed mistakes in our opponent.
Excellent examples of this are to be found in all personal quarrels.
Unless we are possessed of an unusual degree of self-awareness we shall never see through our projections but must always succumb to them, because the mind in its natural state presupposes the existence of such projections.
It is the natural and given thing for unconscious contents to be projected. ~Carl Jung, CW 8, Para 507