Suppose that, with the exception of some sore or painful spot, we are physically in a sound and healthy condition. The pain of this one spot will completely absorb our attention, causing us to lose the sense of general well-being, and destroying our comfort in life. In the same way, when all our affairs but one turn out as we wish, the single instance in which our aims are frustrated is a constant trouble to us, even though it is something quite trivial.
