Nagarjuna used the following analogy to describe man’s desire in the treatise entitled Letter to a Friend (Suhrlekha). People who suffered leprosy, a disease caused by bacteria, would feel extremely itchy and painful when the symptoms flared up. In order to alleviate the pain, many lepers would go very close to the fire. The bacteria being stimulated by the heat then became much more active and made the patients suffer even more. This analogy actually hints at man’s desire. We have always thought that money can buy us happiness and so we strive all the time to make more money. But the truth is that being rich often makes us even more miserable.

- Quote from The Right View, "A Buddhist’s Mode of Life"