Quick, look down at your ring finger (if you have a y chromosome). How does its length compare to that of your first/index/pointer finger? That length ratio can tell you things, but in the end you may wish you'd not read this post.
Several different studies have correlated the length ratio of ring/index fingers to certain health and/or personality characteristics, generally as a result of in-utero testosterone exposure levels, including athletic ability, aggression/lack of generosity, aptitude for math, heart disease, earning power, and more recently, an increased chance of prostate cancer.
See, there, now don't you feel better? Stupid science. I'd much rather at least the illusion of free will. 🙂