Spaceflight will never ...

Spaceflight will never tolerate carelessness, incapacity, and neglect. Somewhere, somehow, we screwed up. It could have been in design, build, or test. Whatever it was, we should have caught it. We were too gung ho about the schedule and we locked out all of the problems we saw each day in our work. Every element of the program was in trouble and so were we. The simulators were not working, Mission Control was behind in virtually every area, and the flight and test procedures changed daily.
 Gene Kranz

Quotes from the same author

Failiure is not an option.
 Gene Kranz
There is no achievement without risk.
 Gene Kranz