Pride

The devil laughs. He is perfectly content to see you becoming chaste and brave and self-controlled provided, all the time, he is setting up in you the Dictatorship of Pride – just as he would be quite content to see your chilblains cured if he was allowed, in return, to give you cancer: it eats up the very possibility of love, or contentment, or even common sense. (C.S. Lewis, Mere Christianity)