Human beings have a habit of compulsive thinking that is so pervasive that we lose sight of the fact that we are nearly always thinking. Most of what we interact with is not the world itself, but our beliefs about it, our expectations of it, and our personal interests in it. We have a very difficult time observing something without confusing it with the thoughts we have about it, and so the bulk of what we experience in life is imaginary things. As Mark Twain said: “I’ve been through some terrible things in my life, some of which actually happened.” The best treatment I’ve found? Cultivating mindfulness.