I have been dwelling on a facet of skill that I've labeled unpredictability. I have been coaching kids on what makes a player skillful in association football compared to less skilled ones, and one central aspect seems to be unpredictability. This aspect seems to apply to many other endeavors, like writing, humor, fighting, and chess: if your opponent or audience knows what your next move is, then you are nowhere near top level. I'm new at coaching and find it rewarding to spread Peter Ralston's ideas about principles whenever I find the chance