From page 71 of The Happiness Hypothesis: Finding Modern Truth in Ancient Wisdom, by Jonathan Haidt

Each of us thinks we see the world directly, as it really is. We further believe that the facts as we see them are there for all to see, therefore others should agree with us. If they don’t agree, it follows either that they have not yet been exposed to the relevant facts or else that they are blinded by their interests and ideologies. People acknowledge that their own backgrounds have shaped their views, but such experiences are invariably seen as deepening one’s insights; for example, being a doctor gives a person special insight into the problems of the health-care industry. But the background of other people is used to explain their biases and covert motivations; for example, doctors think that lawyers disagree with them about tort reform not because they work with the victims of malpractice (and therefore have their own special insights) but because their self-interest biases their thinking. It just seems plain as day, to the naive realist, that everyone is influenced by ideology and self-interest. Except for me. I see things as they are.

If I could nominate one candidate for “biggest obstacle to world peace and social harmony,” it would be naive realism because it is so easily ratcheted up from the individual to the group level: My group is right because we see things as they are. Those who disagree are obviously biased by their religion, their ideology, or their self-interest. Naive realism gives us a world full of good and evil, and this brings us to the most disturbing implication of the sages’ advice about hypocrisy: Good and evil do not exist outside of our beliefs about them.