Mark Twain Quote
I wanted to damage every man in the place, and every woman—and not in their bodies or in their estate, but in their vanity—the place where feeble and foolish people are most vulnerable. So I disguised myself and came back and studied you. You were easy game. You had an old and lofty reputation for honesty, and naturally you were proud of it — it was your treasure of treasures, the very apple of your eye. As soon as I found out that you carefully and vigilantly kept yourselves and your children out of temptation, I knew how to proceed. Why, you simple creatures, the weakest of all weak things is a virtue which has not been tested in the fire.
"The Man That Corrupted Hadleyburg", ch. III, in The Man That Corrupted Hadleyburg and Other Stories and Essays (1900).