We need fear, it stops us from doing stupid stuff like jumping off a building with a safety net. But it needs to be rational fear.

My irrational fear of flying is stopping me from going abroad. My irrational fear of travelling on trains is causing my commute to work to be much longer than it needs to be. My irrational fear of needing to have everything in the house has caused me so many miserable evenings, late night dashes to shops and pointless purchases.

If I had played it safe I would have stayed in my old job. That would have been, quite frankly, disastrous.
I think I was so bored in my life that my body found things to be afraid of just to get the thrill of fear. I NEED challenges or my mind makes them up for me.
Fear is exhilarating and motivating, as long as its evened out with fun and rest.