Gilbert K. Chesterton

We learn our virtues from our friends who love us; our faults from the enemy who hates us. We cannot easily discover our real character from a friend. He is a mirror, on which the warmth of our breath impedes the clearness of the reflection.

Parading our own brilliance and exulting in other people's errors is not very nice. For that matter, even wanting to parade our own brilliance and exult in other people's errors is not very nice, although it is certainly very human.