Both our notion of ourselves, and our personality, are of the nature of the level of existential reality we call thinking. While our ego is a notion, our personality is an albeit ineffable reality. Moreover this mental formation, emerging within the momentous global thinking of the universe, itself evolves by disintegrating and reconstructing itself recurrently in the forward march of becoming. This is like the sequence of notes we perceive as a melody, or the cliches of a film that we perceive as a continuity, failing to grasp the discrete units in the series. Buddhists emphasize the ephemeral nature of all formations, physical and mental.
Illusion is seen as the error of hanging onto that which is elusive.
It is an evolving reality transpiring through vanishing outbursts, like a tide erupting as evanescent waves. Such is the elusive nature of our personality, which is our realization configured in a formative process in a fluid structure. Our identification with it gels it to the point of psychological sclerosis, hence Buddha's deprecation of the hoax of identification. This is where our ego which is what we erroneously identify with hampers the unfoldment of our personality. Our sense of what we could be if we would be as we might be frees us from this imbroglio.