False ego is the pure soul’s illusory identification with the subtle material mind and the gross material body.

False ego is the pure soul’s illusory identification with the subtle material mind and the gross material body. As a result of this illusory identification, the conditioned soul feels lamentation for things lost, jubilation over things gained, fear of things inauspicious, anger at the frustration of his desires, and greed for sense gratification. And so, bewildered by such false attractions and aversions, the conditioned soul must accept further material bodies, which means he must undergo repeated births and deaths. One who is self-realized knows that all such mundane emotions have nothing to do with the pure soul, whose natural propensity is to engage in the loving service of the Lord.

Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Eleventh Canto, Chapter 28 – Text 15.