He said that it was very difficult to become an astronaut. I said that I knew. You had to become an officer in the air force and you had to take lots of orders and be prepared to kill other human beings, and I couldn't take orders. Also I didn't have 20/20 vision, which you needed to be a pilot.
Mark Haddon, The Curious Incident of the Dog in the Night-Time
humorous, subtlety