Bonus items in video games are almost always hidden behind some array of dangerous obstacles. On first play, most people would avoid them. The primary goal, after all, is to complete the level. But when you immerse yourself in the virtual world for long enough, you begin to see the obstacles as goldmines. You know that the only reason that lava pit, or wall of bees, or freakish baddie is there is to guard the prize on the other side.
Maybe the first time you found one was on accident, when you lost control and saw the prize on the other side as you were falling to your death. So you went back. Your instincts began to invert themselves. Now, instead of running away from harm, you plow straight into it. You sacrifice your health based on some kind of faith that, once you break through, whatever is on the other side will restore you and give you powers you never knew existed—strength that will make the obstacles you once feared seem benign.