When I come to my evening prayers and try to reckon up the sins of the day, nine times out of ten the most obvious one is some sin against charity; I have sulked or snapped or sneered or snubbed or stormed. And the excuse that immediately springs to my mind is that the provocation was so sudden and unexpected: I was caught off my guard, I had not time to collect myself. Now that may be an extenuating circumstance as regards those particular acts: they would obviously be worse if they had been deliberate and premeditated. On the other hand, surely what a man does when he is taken off his guard is the best evidence for what sort of a man he is? Surely what pops out before the man has time to put on a disguise is the truth? If there are rats in a cellar you are most likely to see them if you go in very suddenly. But the suddenness does not create the rats: it only prevents them from hiding. In the same way the suddenness of the provocation does not make me an ill-tempered man: it only shows me what an ill-tempered man I am.

C. S. Lewis Mere Christianity