On that note, I noticed a Marie Curie quote today: "Nothing in life is to be feared, it is only to be understood." My immediate reaction to that statement was, 'what nonsense! Of course things are to be feared! Here, let me list some...' But then I took five seconds, and the wisdom appeared. For most of us, the natural state is to fear the unknown - be it a new experience, a strange person, or the nebulousness of the future. But through understanding, we fear less (and live more). That can mean understanding what drives our fear, or learning about the new/unknown until it is un-feared.* It doesn't mean we won't still worry and fret, but we can at least manage it. Fear should not hold us back, but there is a place for healthy precaution - say, around radiation, which killed Curie after she devoted her life to understanding it.
*New hipster band name: The New Unknown. Also you would be correct in thinking that un-feared is not a word, but what is the opposite of fear?