What is Ego?
Humans have varied beliefs / understanding about Ego. Many people consider "bad attitude" as ego, which it is not. Many others consider "pride" as ego, but being proud is a good thing. That's not what ego is.
If you look at it deeply, Ego is: living in the illusion (rather, delusion) that you're a physical human being and forgetting the non-physical aspect of the self i.e. considering yourself to be something that you're actually not. When you live in such an illusion, you consider only physically tangible conditions as the ones that fulfil you. Then you gradually become dependent upon them for your happiness. This is conditional living, and it only makes you sad over a period of time.
Fear is the first manifestation of ego. Fear of losing one's identity or image that one has created over a period of time. Fear is the root of many other negative beliefs, thoughts, and emotions that one experiences on a day-to-day basis. Thoughts of pessimism, unworthiness, insecurity, hopelessness, victimization, etc. are nurtured in the mind, leading to bad-feeling emotions, such as sadness, guilt, hatred, anger, and so on and so forth.
It is, therefore, very important to understand one's true identity, which is non-physical, powerful, which enables one to make corrections to the self's belief systems that can change one's life. You don't need to fear your own ego or try to run behind working on eradicating it. You can make it your friend, your best friend, and keep an eye on your day-to-day Thoughts, Feelings, and Beliefs to see where you can potentially change yourself for the better.