tldr:

The involvement of astronauts and ground support teams in the design process was a key factor in producing spacecraft that performed superbly.

The Apollo program's design principles stressed simplicity, and the use of established technology for areas in which performance and reliability goals had already been realized.

The primary consideration governing the design of the Apollo system was that no single failure should cause the loss of any crewmember, prevent the successful continuation of the mission, or prevent a successful abort of the mission.

Flight control in the Apollo program was a significant factor in its success, with approximately 80 percent of all problems encountered in flight having been previously discussed, documented, and simulated before the flight.

The remaining 20 percent of the problems readily yielded to the same logic, and decision-making procedures followed to arrive at pre-mission decisions.

The Apollo program was an unprecedented challenge to the ingenuity of engineers and scientists, and the ambition to reach the moon was a challenge in itself.

The program's success was a testament to the power of collaboration, innovation, and perseverance in the face of seemingly insurmountable challenges.