People have a hard time defining fear. What I do know is that when I fear something, I try to avoid it. If I fear spiders, it is based on my knowledge that they will most likely bite me and cause great pain. This has happened to me before. Many people would call this a rational fear because I know that spiders are a real threat based on experience.
At the same time, there are also irrational fears. This is usually a fear based on ignorance. Examples would be fear of women, fear of white humans, or fear of gay humans. I do not call this fear but prejudice. What I have learned is that I am afraid of all humans because they do things that are totally out of my control. My past ideas that I can predict future harm from a special group of human are now irrelevant. Such fears lead to hatred and violence.
My fears are not limited to spiders and humans. I fear all kinds of things such as cars, television, and sex. I openly admit my fears because I am honest. While I may avoid things intentionally because of my fears, I do not let my fear stop me from doing what I choose to do. My fear of cars is irrelevant when I am in a situation where riding in a car is the only way that I can get somewhere. I also must avoid cars when I am walking somewhere to avoid being instantly killed.
Most of the time my fears are irrelevant because I place higher priority on relevance, truth, and goodness than I do on predicting the future. I believe that perfect relevance casts out fear.