When we're frightened of something that can't really harm us - like spiders - or something we may do nothing about - like old age - then our fear is unhealthy, for it only makes us distressed.
But, when someone stops smoking since they're afraid of getting lung cancer, this is a healthy fear.
We have several fears-fears of act of terrorism, fear of passing away, fear of being apart from individuals we love; fear of losing our job, the list is perpetual! Many our fears are rooted in delusions- confused ways of viewing ourselves and the world around us. If we learn take control, and relax and finally wipe out these delusions, the unhealthy, is annihilated.
Even so, we need the healthy fear. For example, there's no point in a smoker becoming terrified of dying of lung cancer unless there's something that he or she will do about it, i.e. stop smoking. If a smoker has a sufficient fear of passing away of lung cancer, he or she will adopt steps to kick the habit.
Even as a smoker is vulnerable to lung cancer due to smokes, it's true that we're vulnerable to risk and harm, we're vulnerable to ageing, sickness, and pains that come from the delusions of bonds, wrath, and ignorance.
We might choose to live in self-denial and thereby give up what control we have, or we may choose to recognize this vulnerability, admit that we're in danger, and so determine a way to avoid the risk by removing the real causes of all fear (the same as the smokes). In this way we gain control, and if we're in control we have no cause for fear.
A balanced fear is healthy as it serves to cue constructive action to avoid a true danger. We only need fear as an impulse till we have removed the causes of our vulnerability through attaining spirituality, inner peace and gradually strengthening the mind. Once we do this, we're fearless as we no longer have anything that may hurt us.
Staying afraid of things we don't have control over is unhealthy fear, a survival mechanism failed. Sometimes this can be healthy and normal. However fear has become rampant when it never leaves us. It becomes a shadow, forever alongside you.
Fear crushes self-reliance, enthusiasm, and initiative. It promotes procrastination, and leads to weak character. It defeats love, fogs memories, and finally leads to misery and sadness.
However take heart, for a lack of courage is nothing more than a state of mind. It may be mastered.