I've always been interested in psychology.  I always wanted to know why we do/think what we do, especially when it comes to behavior that defies what society deems "right". 
For example; Why do we ignore statistics?  Why do we believe we are the exception to those facts?
I struggle with this personally as a smoker.  I know that smoking is bad, but deep inside, I don't think about anything bad happening to me.   If I was scared I would make a better effort to rid myself of this addiction. But even as I write this, I have a cigarette hanging from my lips.  I'm going to smoke it, and in about an hour, I'm going to have another one. 
When someone says "I just don't think about it", and "I didn't think it would happen to me", turns out, that's the truth.  Our brains have prevented us from worrying about the bad things, until they actually occur.  When we learn that we are at a higher risk than what we assume, our brains literally do not process it the same way we do when our minds are put at ease by learning that we are at less risk than previously thought.  
The following is a clip from the "Through the Wormhole" series that explains how our brains process negative information opposed to positive. http://www.youtube.com/watch?v=7cp00HMll04&feature=youtu.be&t=16m28s

This conclusion goes on to explain why most of us ignore the warnings about the economy, global warming, health risks, etc.   We don't change our behavior when faced with fact, because we simply do not believe that we will be one of those who will be affected.  Chances are, you're thinking right now that you're part of the 20% of people who do not have this "Optimism bias" going on inside your head.