Cognitive methods are a new tool for expanding self-control in many areas. Some fears are unreasonable and harmful, some are reasonable and helpful, e.g. the anorexic's totally unreasonable fear of food making her fat and the heart attack victim's reasonable and helpful fear of high fat food. In time, the anorexic can change her mind about her body and the person with a heart condition can forget to watch his diet. There are many other mysteries about fears. New conditioning theories help explain these things.
Many people are afraid of snakes or mice but have never been bitten.
Almost no one who is afraid of flying has been hurt in a plane crash. Rimm, et al. Research also confirms that simply thinking about all the horrible things that could happen in a scary situation, say giving a speech, can increase your fear response. If you went to the dentist several times before experiencing serious pain, that might prevent a CR of fear. Giving people information about scary medical procedures can reduce their fear or panic them.