I remember being told, many years ago in psych class, that any given individual has a certain success probability for any given action.
Thus, for an individual called LC, the success probability of action A might be 70%. If LC is pessimistic, she will decide to minimise her attempts in order to minimise her failures. Thus, she will try perhaps 10 times, so that she only fails 3 times. As a result, she will only succeed 7 times.
Another individual, called M, might have a success probability of only 40% for the same action A. However, M might be optimistic, and decide to maximise the number of attempts in order to maximise the number of successes. Thus, M makes 100 attempts, failing 60 times, but succeeding 40 times.
Fear is all about pain, and it is a perfectly natural response to the negative stimulus. However, one of the great joys of human consciousness is our ability to reprogramme our own responses.
Some kinds of pain are good, because they lead to progress.
Of course, the flipside to the aphorism “That which does not kill us makes us stronger” is the comment “That which does kill us makes us dead.”