John Dickson was walking down the street with his friend Len when a cute, friendly, little dog ran over to them. Len knelt down and petted the dog, but John froze and backed away in terror. Although the dog was clearly not a threat, John felt so terrified that bis heart began pouhding He broke out in cold sweat and he felt like he was about to faint Why did John have such an extreme reaction to such a harmless animal? John has a phobia,of dogs.