This is going to be a little bit science heavy but hopefully by the end of this, you'll have a better understanding of your teenager's motivations, why they act like they have zero caution or sense (read: risk takers), and why they are actually not that different than we (sane) adults are.  Question to consider: What motivates you?  I am assuming you are a mature, forward thinking, capable adult and you consider motivation to come from different intrinsic and extrinsic source