We are incarnated in animal bodies, and fear is an instinct of animal bodies. As babies and infants we are very open to absorbing the feelings and experiences of others, and in our current human "civilisation" these influences are predominantly based on fear. So we soak up lots of fear, and gain the habit of fearing.
But this is not the only way we can be. As divine eternal beings our primary quality is love - true love, which is selfless unconditional love.
I am learning to dismiss fear (unless there is a very good reason for it - eg about to walk over a cliff!), and to not make any decision based on fear. Love trumps fear every time.