Perhaps one of the most important yet invisible techniques of self defense (protective offense) is understanding the ins and outs of your own powers of perception and learning to trust your instincts. I think it's crucial to examine our own minds and decision-making processes otherwise the result is a false sense of empowerment, false sense of security, etc.
As Kathryn Shulz says, "Being wrong feels a lot like being right." Her point is we often don't notice we're wrong until something happens or someone else notices.
Everyone is wrong sometimes, probably most of the time, which is why we should question our assumptions and convictions at all times.
Here is a TED Talk that illustrates an important part of this equation.