Small Self Identification
When awareness is exclusively identified with (or temporarily caught up/lost in) the small self, there is a sense of separation. Awareness functions in a dualistic way. We see the world in terms of absolute separations - in you and me, body and mind, creator and creation, life and death, good and bad.
We see certain qualities in others and not in ourselves and the other way around, and we assign values to these qualities. When I see something desirable in you and not in me, it gives rise to admiration or envy. When I see something desirable in me and not in you, it gives rise to pride and arrogance. When I see something undesirable in you and not in me, it gives rise to judgment. When I see something undesirable in me and not in you, it gives rise to guilt and shame.
And all of this naturally gives rise to a desire to fix ourselves. We want to acquire more of the desirable qualities, and less of the undesirable. We want to be "good". We want to be healed and fixed. As so many have pointed out, this gives rise to the whole self-help industry.
This may work to some extent and for a while, but is never in the end quite satisfactory. There is always someone who has it better than us, always something more to achieve and acquire. It is samsara - a nagging sense of uneasiness. Something is never quite right.
Nature of Mind
When we awaken to the nature of mind, we find another "ground" - one that is distinct from the small self. And we discover that everything is perfect as it is. It just is - complete as it is.
For the first time, we gain some overview and a perspective of the small self. We still see it with its peculiar characteristics and flaws, but nothing seems so serious anymore. We are more than the personality, and that which is more than the personality is perfect as it is and knows that everything is perfect as it is.
There is still room for improvement, and we may still engage in various ways to "improve" the small self, but now it is for a different reason. Now it is to finetune this vehicle for the expression of the nature of mind, or Big Mind.
And there is a new focus as well - to just be with whatever is. To rest in the nature of mind while being actively engaged in the world.