Fear is our life-saving instinct, this is why most of us are afraid of something. If you are not afraid of anything then this is frightening and according to psychotherapy, this is an illness.
If you are not afraid of anything then you are doing things without even think of them this way you are putting yourself in dangerous situations. Also not thinking of the consciences would lead to bad circumstances.
When you are frightened then your instinct of self-preservation activates and you are starting to think about the possibilities and what can happen and how to avoid it in order to keep yourself alive and safe for a longer time.
However, fear has its cons.
The worst thing is that when we are scared the most we stop to think and can’t get proper decisions.
Also sometimes we took too much time of being afraid of something that might not happen or is meaningless. People are mostly scared of changes in their life we are afraid of doing something that can reflect on the standard way of our life.
There are a lot of books that can help us understand which are the important things to be afraid of and how to avoid to be afraid of shadows.