Traffic rules - you are prone to accidents if you don't understand them. For example, from 23:00 to 3:00 in the morning is the time when the gallbladder and liver meridians are most active. The liver and gallbladder need to return blood, "lie down to return blood, stand up to supply blood". If you lie down at around 22:00 every night and stay quiet without talking, by 23:00, you would have fallen asleep. The liver and gallbladder start to return blood, filter out the toxic blood, and produce fresh blood. You can live to be a hundred years old without getting gallstones, or hepatitis and cysts. But if you stay up late every day until 1...