One of the biggest reasons why ego is your enemy is that it keeps you out of touch with reality.
Your ego is what prevents you from hearing critical but necessary feedback from others.
Ego makes you over-estimate your own abilities and worth, and under-estimate the effort and skill required to achieve your goals.
Ego creates unrealistic expectations and entitlement.
Ego makes you dependent on external validation.
We all have ego, our job is to control our ego not to get out of control.
Our greatest enemy is the enemy within, our ego. We have to tame our ego all the time.