Risk is part of every human endeavor. From the moment we get up in the morning, drive or take public transportation to get to school or to work until we get back into our beds (and perhaps even afterwards), we are exposed to risks of different degrees. What makes the study of risk fascinating is that while some of this risk bearing may not be completely voluntary, we seek out some risks on our own (speeding on the highways or gambling, for instance) and enjoy them. While some of these risks may seem trivial, others make a significant difference in the way we live our lives.
Given the ubiquity of risk in almost every human activity, it is surprising how little consensus there is about how to define risk.