I gave blood yesterday. I hate needles and can't even look when they put it in and take it out.
But people need blood more than I need to nurse my fears, which I suppose isn't a bad metaphor for doing the important things in life--leading, being in relationships, contributing my gifts, loving, etc. At any point I can say no to those things because I might get hurt. But (and this is universally true), people need my gift more than I need to protect it.
"Now to each one the manifestation of the Spirit is given for the common good."
1 Corinthians 12:7