Fear

Fear is a good instinct. Our ancestors needed it to survive and modern man probably isn't all that different. Just the things we fear have changed. Or have they?
We may have that instant fear when a passing car almost hits us or when there is a weird guy following us on our way home in the middle of the night. We fear that either we, or those we care about, might get hurt, accidentally or by someone's purposeful action. So we look twice before crossing the street and we take a pepper spray when going out and we hope that people we care about do the same. We take precautions to diminish the threat. Or make ourselves believe that it did.
Then there is the kind of fear that is paralyzing - when we find out that death is real and that it may soon take someone we love. There is not much we can do, we just have to wait and see. Fear is combined with helplessness, the worst kind of fear there is.
And then there are those fears that concern day-to-day stuff. We fear that we will lose something valuable, fail an exam, get rejected, never see the Sun rising over Mount Fuji, what have you.. Fears that are probably not very helpful, but that we can't seem to shake off. Because they are fears of habit.
So, some fear is good, but fear that paralyzes, prevents us from acting, from doing things we want to do, that is the kind of fear we should try to shake off.