The ego isn't a bad thing. If we didn't develop a strong ego, a strong sense of self, we wouldn't be able to relate to and engage with the extremely powerful and archetypal forces (both dark and light) of the unconscious. If we don't have a strongly developed sense of self (even though it is not, ultimately speaking, the true self), we will get overwhelmed and taken over by the powers of the unconscious such that we will compulsively act them out.