It's our ego that ultimately protects us in society. It acts as a bubble and a filter that chooses what we want or not want to hear about ourselves. So if someone says your nice, you can be like "yea that's me" or "no, i'm not nice, i'm a tough guy", either way you select what you want to hear about yourself, thus feeding your ego. However, you can feed into your own ego, but it's not as satisfying as someone else doing it for you. An ego is necessity for life, big or small, and without it you wouldn't be who you are today.