Fear is never a good motivator. There are people who will tell you otherwise, who think fear is good, because it may drive you to work, to save, to avoid bad deals, to avoid entangling … anything.
To illustrate: imagine a man encountering a swarm of bees. His fear causes him to breathe more quickly, and the carbon dioxide as he does, attracts more bees. He runs, reactively, and the bees go with him. He doesn’t know whether he’s running to or from the hive.
Now imagine the man who feels the impulse to fear, but overcomes it. He surveys the situation, uses any knowledge he has, and certainly his rational powers. In this case, maybe he knows enough to hold his breath. He identifies the direction of the swarm, and runs as fast as he can in the other direction, trying to reach the threshold of pursuit.
Life is full of bee swarms. You can’t let fear determine your reaction. It’s easier, it feels natural. But it isn’t. The natural thing, for a human being, who has neither claw, nor fang, nor fur, is to restrain fear, think, and act deliberately.