To keep our body healthy, our immune system creates molecules called free radicals that fight viruses and bacteria. However, when environmental factors such as pollution and pesticides cause free radical production to become excessive, the molecules attack not only virues and bacteria but good cells and vital tissue as well, causing illness, premature aging, cancer, and other diseases.

Ego is free radical.

In the right amount ego is inherently positive and provides a healthy level of confidence and ambition-driving out insecurity, fear and apathy. But left unchecked, it goes on a hunt. The primary “cells” ego attacks are our talents and abilities-either through overconfidence and giving the false illusion we’re better than we actually are, or by robbing us of confidence so that we lose trust in our ability to use those talents to capacity.

David Marcum, Steven B. Smith — Egonomics