Driving around the other day in heavy traffic, I thought about how intricate the road system is and how it grew incrementally. No piece of the system is particularly difficult to understand -- drive on the right side of the road, stop at stop signs, signal when you turn, faster vehicles to the left lane in a four lane, yield to the vehicle on the right at a four way stop if you both reach it at the same time, and so on -- but when you put all the pieces together, the total effect is mind-bending.
Of course, systems fail. Extremely heavy traffic and rule-breaker drivers can cripple a system, but it will recover eventually. Pieces can falter, but the system continues.
If you were an alien fresh to Earth, you would look at our highway system and think a genius had put it together, but it was only time and codified convention. Life is like that; it grows and becomes more complex. The trick is to keep track of the parts that matter, the ones that you can control. The system is too big for overall control, but the bits and pieces are definitely within our grasp.