These are the two ideas you should keep at the very front of your mind and think about. One is that things in the world do not touch your spirit, but stand quietly external to it; that which disturbs us comes only from the opinions within us. Second, everything you see changes in a moment and will soon be gone. Keep in mind always how many of these changes you have already seen. The world is constant change; your life lies in your opinion. Marcus Aurelius, Meditations 4.3.4
