A study not long ago (sorry, I don't remember the source) showed that, out of the people they surveyed who felt they were good judges of character, 2/3 turned out to be wrong. And I believe it. I've seen a lot of people who say, "No, he wouldn't lie," or "She wouldn't do that," or "He would never molest a child," etc. How many times have you seen on the news, people who are shocked to learn someone they know--a relative, neighbor, friend, etc.--committed a heinous crime? You can't truly know what's in a person's head. Too many people think they'd be able to see the signs of someone who would be dishonest, violent, "sick," etc., but very often, you can't.