When my dad signed up for the Army/Air Corps, they gave him some sort of a test on which he scored very well. They decided to make a pilot of him and sent him to school. While in training, he touch a wing in a landing. There was little damage but that was that. He washed out. They sent him to navigator school instead.
I asked him once if he had regrets. "No, no regrets," he said. "Nobody who survived had any regrets." For the rest of his life he insisted, however, that the accident would never have happened if he'd known ahead of time how to drive a car. "I had no experience with a steering wheel, depth, or travelling at high speed," he said.
Once missions began, everybody was very superstitious about their own crew, believing it to be special, or lucky. Nobody wanted to fill in for anybody else. Once the mission requirement was met, crews were sent home... supposedly for good though no one believed it. Two guys my dad was friends with were in that position except that they'd missed one or two flights due to illness and had to make them up. They were assigned to a new plane which was promptly shot down. No survivors. That, of course, weighed heavily on everybody else and their inclination to ever admit that they were too sick to fly.