Words like Gene, Neuron, DNA or Hormone are now used casually even by children. Nature, and in particular humans, are studied using instruments that until recently belonged to science fiction. Knowledge no longer comes by word of mouth, dogma, subjective truth or faith, but thanks to the scientific method which includes double blind studies, skepticism and controlled testing. Thanks to this method in the last century we have discovered that we descend from a single African species, that the star around which our planet rotates is one of a hundred billion stars in our galaxy, in turn one of a hundred billion galaxies in a universe that is 15 billion years old. After millennia of total world poverty, an ever-larger part of mankind goes to school, lives in peace and enjoys some luxuries into old age. I am therefore surprised that in many fields there is suspicion and mistrust concerning the value of the scientific method. Public attention is focused on what is behind the bad news and gives good news for granted. The fact that complications after a vaccine might be one thousand times less likely than after the disease the vaccine protects against, is for many people a reason not to immunize their children. The fact that diseases that killed hundreds of thousands of people in the past have vanished thanks to vaccines is about as important as learning to prepare whipped cream. What really bothers these people is that unreliable sources with no supporting statistical evidence speak about a connection between the measles vaccine and autism. Why does the Negative win over the Positive? In the history of human evolution, the price paid when overestimating the importance of a threat was surely far less than that of underestimating it. We are programed to detect an angry face in the crowd rather than a happy one, to feel pain and not non-pain, to refuse an ice cream on which a drop of mustard fell and accept mustard that has a drop of ice cream.