To refuse the dark side of one’s nature is to store up or accumulate the darkness; this is later expressed as a black mood, psychosomatic illness, or unconsciously inspired accidents. 

We are presently dealing with the accumulation of a whole society that has worshiped its light side and refused the dark,

and this residue appears as war, economic chaos, strikes, racial intolerance.

The front page of any newspaper hurls the collective shadow at us.

We must be whole whether we like it or not; the only choice is whether we will incorporate the shadow consciously and with some dignity or do it through some neurotic behaviour.

Robert A. Johnson, Owning Your Own Shadow