“Nobody's easier to fool, than the person who is convinced that he is right.”
“It's easier to fool people than to convince them that they have been fooled.”
“Every fool stands convinced; and everyone convinced is a fool. The faultier a person's judgement the firmer their convictions.”
“Those who are not angry at the things they should be angry at are thought to be fools, and so are those who are not angry in the right way, at the right time, or with the right persons.”
“...and the funny thing was that people who weren't entirely certain they were right always argued much louder than other people, as if the main person they were trying to convince were themselves.”
“The easiest thing in the world is to convince yourself that you're right. As one grows old, it is easier still.”