Having your behavior influenced by a fairy tale fear is the negative impact. Carrying phobias because you can’t see the negative impact isn’t healthy or wise. The perception of negative impact will be biased by the fear itself through the coping systems it produces, leaving you blinded to the negatives and blinded to the opportunities the phobia takes from you. Both of which take from the potential of your life. I would expect a person with these fears to have a difficult time seeing the negative impact if they’re afraid because seeing the negatives would undermine the coping system and bring the fear out.