Unless we are fully integrated personalities, resting in God, clear and confident in our identity as individuals, full of virtue and free of all compulsions and destructive dynamics, we have interior work to do.
A big part of that work involves coming to true self-knowledge and genuine self-acceptance. Both are prerequisite for the sincere gift-of-self that is our fulfillment as persons. Neither is easy to attain, because, thanks to our fallen condition (plus the shortcomings of our upbringings), we are afflicted with confusion, error and illusion about ourselves. To a greater or lesser extent, most of us are double-minded, deluded, and in denial.
In my own interior work, I've found it helpful to distinguish both conceptually and existentially three "selves" at issue in the soul.
Ego is the selfish self, the demanding, voracious, competitive or obsequious self; the self that masters and slaves, uses and abuses, connives and manipulates to get what it wants—power or pleasure or prestige or protection. It has no concern for others, except in terms of what it can get from them. It doesn't serve or share, it takes and devours. It doesn't admire and cherish, it scoffs and exploits. It disregards objective goods and values, moral laws and norms. Everything is subordinated to ego-interest.
Egotism is the mode of being and acting in which we "live for self to the contempt of God" (and others). It's the way of hell—and a kind of force within each of our souls that has to be consciously repudiated and subdued by grace.
The false self is an image we create of ourselves. It's typically a mixture of what we've been taught and/or believed and what we want to be true and want others to believe about us. It is the "willed self" we present to the world. It's a facade, though sometimes only unconsciously so. Most of us are unaware that we are hefting a false self—striving to maintain an image, even in our religious lives.
The false self is recognizable by its inefficacy. It dwells in theory, abstraction, and appearances; it lacks traction in the concrete. When we're operating from the false self, we experience a tension and disconnect between the idea we have of ourselves and the way we actually feel and behave and react. The false self is the one who says, "I'm not mad," or "that's fine," expressing not our true feelings, but our notion of what we should feel or what we wish we felt. The false self is threatened by criticism; it worries about what others think; it is anxious, judgmental, brittle, and insecure. It's the self that gets enmeshed in dysfunctional relationships.
The true self is the unique and irrepeatable (plus limited and imperfect) person we're actually created to be; its roots are in God. Its reality is revealed in and through our feelings. Its authenticity is recognized in the efficacy of its free choices and responses. It's the ground of right relations and communion with others, the locus of love in our lives.
In my experience, believing Christians are generally pretty good at recognizing and repudiating the ego. We know it's not okay to live for self to the contempt of God or to treat others as mere objects. We reject that way of living.
We have a much harder time coming to terms with the false self, because it's so deeply and subtly entwined with our sense of identity. Ridding ourselves of it means letting go of long-cherished illusions we have of ourselves in favor of a reality that seems (at first) so much less impressive, less valuable, plus weaker, more vulnerable and more dependent.
It's extremely painful. But it's the only way to God and communion. A passage in Spe Salvi lays it out powerfully.
47. Some recent theologians are of the opinion that the fire which both burns and saves is Christ himself, the Judge and Saviour. The encounter with him is the decisive act of judgement. Before his gaze all falsehood melts away. This encounter with him, as it burns us, transforms and frees us, allowing us to become truly ourselves. All that we build during our lives can prove to be mere straw, pure bluster, and it collapses. Yet in the pain of this encounter, when the impurity and sickness of our lives become evident to us, there lies salvation. His gaze, the touch of his heart heals us through an undeniably painful transformation “as through fire”. But it is a blessed pain, in which the holy power of his love sears through us like a flame, enabling us to become totally ourselves and thus totally of God. In this way the inter-relation between justice and grace also becomes clear: the way we live our lives is not immaterial, but our defilement does not stain us for ever if we have at least continued to reach out towards Christ, towards truth and towards love. Indeed, it has already been burned away through Christ's Passion. At the moment of judgement we experience and we absorb the overwhelming power of his love over all the evil in the world and in ourselves. The pain of love becomes our salvation and our joy.