002. Attempting to Start World War III, Because Evil - You Only Live Twice
The Plan: Acting from his volcanic lair, arch-villain Blofeld and his terrorist organization SPECTRE has been abducting space craft in order to goad the US and USSR towards nuclear war with one another. They do so at the behest of an unidentified third power - presumably China.
The Idiocy: You know what's a really poor way to go about taking over the world? Destroying it utterly. Absolutely no one actually stands to gain from World War III, especially not China, who would most likely have a few spite missiles tossed their way just for the heck of it in the event of a nuclear exchange. Blofeld and his cronies can have fun playing cards in the ashes, waiting to die of radiation poisoning (why do movies forget that that's a thing?).