you must have fear of dog if you have ever been bitten by one. however, if you avoid walking down street where you think there might be a dog, you may have a phobia which is an irrational reaction to an object or situation that is not necessarily dangerous. A person whose fear has started to change his or her life probably has a phobia. DIFFERNT SURVEYS SAY THAT between 10 and 80 percent of us have at least one phobia