Acharya Prashant explains that the ego becomes so accustomed to its own littleness, powerlessness, and worthlessness that it cannot tolerate a situation where its usual excuses are no longer valid. He uses an analogy of a fat man: if you tell him he cannot run fast, he is happy because it confirms his limitations and powerlessness, which he is comfortable with. This statement of his incapability aligns with his current state. However, if you tell the same man that with one year of effort, he could become the next Usain Bolt, he will be scared. This fear arises because achieving such potential would require him to "pay up," meaning he would have to shed a lot and give up a lot. The ego is afraid of this process because it does not want to give up its habits and current state. This fear of letting go is the core of the issue. The speaker clarifies that the betterment of the ego is, in fact, the reduction of the ego. People inherently want to accumulate and become bigger, not smaller. In the context of the ego, betterment is not about getting bigger but implies getting smaller. Since the ego does not want to be reduced, the prospect of its own betterment becomes a source of fear.