Im reading a book about the Apollo program that focuses mainly on Apollo 11 and I thought this was interesting:
The Apollo 10 lunar lander was not fully fueled to ensure that the crew would not decide to land on the moon (Apollo 11 was the first attempt to actually land on the moon, and had Apollo 10 attempted a landing, they would not have had enough fuel to get off the moon/back to Earth)
The Soviets had planned for an immediate launch to put Cosmonauts on the moon if Apollo 11 was unsuccessful.
HA! you learned! but I thought that was rather interesting