A big ego needs constant confirmation & maintenance

Everybody feels good when their ego receives a confidence boost. 

The real problem appears when you stop feeling good about yourself if the confidence boost is not received. 

Another issue is that, in order to receive the boost, your ego needs an enemy - a situation or a problem to feel bigger or better than. This stops you from enjoying your life and accepting things as they are.

Apart from being conditioned by the need for recurrent boosts, it often happens that this enemy is someone that you might need in the future, but cannot count on him anymore because you already chose the ego.