I have been crewed up with several other rearcrew over 36 years who were scared of flying, and they were often even more scared when "getting back on the bike" after an emergency.
However, much more recently, I myself retired after 9 months of being scared witless on every single flying day. I could not even consider the offer of 5 years more flying service; I simply could not wait to get the last flight done and to stay on the ground for good.