How to delude yourself
Here's a socialization anti-pattern: be judgmental and/or unforgiving. Let it be known that normal, decent, upstanding citizens don't do X, where X is: abandon their religion, hold the wrong political beliefs, not vote at all, do drugs, cheat on their spouses, indulge in adventurous sexual exploits, try polyamory, etc.* Notice how very rarely you hear about your friends doing X! It must be because they're all such normal, decent, upstanding citizens.
"In Iran we don't have homosexuals like in your country," [Iranian President Mahmoud] Ahmadinejad said to howls and boos among the Columbia University audience. "In Iran we do not have this phenomenon, I don't know who has told you that we have it," he said.
Or, of course, it could be that all that stuff happens, but never enters the pure, unsullied perception of the righteous. You can block or minimize entire categories of human nature from your perception. (Another way to achieve a similar effect is to acquire a reputation as someone who won't keep a secret. Either way, people won't tell you sensitive information.)
Sindibad, an ex-Muslim and commenter at Overcoming Bias, describes how he told people of his apostasy:
People whom I knew could possibly open their minds and stop them believing in their faith, I tried to talk to them about it, and succeeded in convincing a few.
Those whom I thought might not get convinced, but would be understanding, I told them the truth, and they never bothered me much.
But for those who didn't look likely to get convinced, or likely to be understanding, I have simply avoided talking to them about the subject, and when they ask, I pretend to be religious.
What a disaster. Avoiding challenging viewpoints is surely not a path to truth.
But how do you know whether you're judgmental? Paul Graham describes the problem in his (highly recommended) essay What You Can't Say:
Who thinks they're not open-minded? Our hypothetical prim miss from the suburbs thinks she's open-minded. Hasn't she been taught to be? Ask anyone, and they'll say the same thing: they're pretty open-minded, though they draw the line at things that are really wrong...When people are bad at math, they know it, because they get the wrong answers on tests. But when people are bad at open-mindedness they don't know it. In fact they tend to think the opposite
I have no profound suggestions on developing open-mindedness that Paul Graham or the fine people at Overcoming Bias can't outdo. But the first step to understanding the world - no matter how you want to judge what you find - is surely to perceive it accurately (to the extent that humans can). So, consider: do people tell you secrets and trust you to keep them? All kinds of secrets?
*I'm not saying that all those things are ok, obviously. I'm just saying: there's a difference between responding "That's interesting. I see it differently. Let's talk about that." vs. "BEGONE, DEMON! YOU INFECT MY EYES.".