Normal” fears vs. phobias or “irrational” fears Experiencing fear in risky circumstances is common and even beneficial. Fear serves a defensive function, triggering the "fight-or-flight" automatic response. We are able to respond rapidly and defend ourselves, with our bodies and minds alert and ready for action. But with phobias, the risk is either non-existent or strongly exaggerated. It's only normal to be afraid of a snarling Doberman, for instance, but being afraid of a friendly poodle on a leash is unreasonable, as you may be if you had a dog phobia.