I saw an interview with the defending professional rock-paper-scissors champion. He said the key to the sport is not knowing what you're going to throw, because your opponent can see subtle movements in your forearm muscles if you plan ahead. If you can surprise yourself, you eliminate your opponent's ability to read you. I think it's wonderful that there's a sport based on convincing yourself to be unpredictable and looking down at your hand and saying, "Oh, look, I just threw rock! I didn't know I was going to do that!"