Playing from memory?
Changing registration in the middle of the piece by hand?
Playing in front of the choir members on short notice?
Sight-reading in public?
Improvising for church services?
When facing danger, there are only two primary reactions humans, like all animals have: flee or fight.
Most people tend to shy away of fearful and insecure situations. Some people, though, seek out danger because they have figured out that mistakes will not kill them.
Acknowledge your fear and use it as a compass. That's how you become fearless.
PS In today's ever evolving world this turns out to be the best strategy.