Bruising the Ego

Why is it that the ego is so easily bruised? To me, it says just how powerful the ego can be and how much control we have allowed it to have over us. I experienced this control recently. I became offended by something not worthy of offense. I must learn to put the ego in the background and prevent it from ruling my life. It's not easy. The ego doesn't like it at all. Until I can immeditately see what is happening when the ego takes "front and center" in my life, I shall continue to be ruled by this selfish, power-hungry part of me.