People who like to do risky things usually are daring and extremist. Also, they could be addicted to it; the more they do it, the more they want to do it. I don't know anybody personally who takes things to the edge, but I guess that they do dangerous things such as bungee jumping for the thrill of it. A new experience, new emotions to conquer themselves. I wonder what it would be like to do some of the risky things