Egoism and self-centeredness work in the subtlest fashion, at least from my point of view... Employing an endlessly adaptable variety of approaches to maintain our illusion of seperatness. One important source for this lies in our perceived failures and successes. When we fail, or feel that we have failed, egoism leads us to consider ourselves to be failures, incompetent, stupid, perhaps even worthless. When we succeed, egoism leads us to inwardly preen, swell with pride, feel invincible, and consider ourselves to be better than others. And then we tell ourselves and others stories of failure or of success. In either scenario we buy into allowing our self-worth and our own reality to be defined by events external to us, by the feedback we receive from the world.
Sorrow for and learning from our mistakes, as well as natural satisfaction in our accomplishments, does not necessary strengthen our self-centeredness. But the great temptation of the poles of success and failure consists of ascribing them to our illusory self, feeling that it is myself who have succeeded or failed, praising or blaming myself, and thereby perpetuating my misguided belief in this mirage of a self.
Neither great success nor continuing failures can fundamentally alter who I am. This is a hard lesson taught by experience. And since most of us never achieve what we define as great success, it remains an unattained goal, forever enticing us to look exclusively to externals for meaning and purpose.