‘The Unconscious’ is basically ‘potential forms of consciousness’ that are prevented from entering consciousness by elaborate egoic mechanisms and repression.
For example: A workaholic may spend his whole day being productive to avoid the dual of feeling worthless.
The being identified with ego always lives in a state of tension and fear, because the unconscious is always threatening the ego by impinging on its boundaries.
So the ego creates elaborate mechanisms to prevent the unconscious (a bunch of repressed/non-accepted potentials of consciousness) from entering consciousness.
A weak ego, with weak repression, becomes desperate to prevent itself from being swallowed by the unconscious. The false identification with the ego, makes us believe we are something i.e. (finite infinite) and have to protect ourselves and fear the (infinite infinite) from swallowing us.