As a matter of principle, we must be wary of anecdotal evidence based on a solitary example or incident. This applies not only to claims of medical breakthroughs but also to political and social issues. Many a time, we form stereotypical image of a community or even a whole nation based on a single incident. Because of human nature, such images are more likely to be negative than positive, as we are more likely to remember any mistreatment we might have received, rather than a polite or helpful act. We hear people claiming that such and such group of people are always dishonest or arrogant or even downright evil. Such sweeping statements are mostly based on a single incident that stems from an unfair and untrue judgment of the concerned group of people. Referring to the matter of health and medicine, one would always meet people who declare that such and such herb is a cure for everything. You would also meet people who declare that a lifetime of unhealthy habits have not affected them, surmising that everyone should indulge in them. Almost every family has a great grandfather who smoked a hookah and lived to the ripe age of 100 years. This applies to great men in history as well. During the Second World War, Winston Churchill visited General Montgomery in North Africa. At dinnertime, Churchill asked Montgomery to join him for drinks. Montgomery replied, "I don't smoke or drink and I am 100 percent fit". Churchill replied, "I smoke and drink and I do it a lot. I am 200 percent fit". -KHALID A., London, UK, via e-mail, June 10.