Star Trek offered hope to a generation who had grown up haunted by the specter of nuclear war. A significant portion of its viewers remembered the 1962 Cuban missile crisis, when the country was readying for World War III. Kids were being taught to “duck-and-cover”; beneath their school desks if they saw an atomic flash. Grim end-of-the-world scenarios were shown in popular books and films. At the same time, our paranoia toward Soviet Russia had reached an all-time high—which may explain why space aliens were generally portrayed in fims as evil monsters, bent on conquering Earth.
And in the midst of this paranoia and fear came a bright message of hope in the form of Star Trek, which said, “Yes, we will survive the atomic age. We will contact other intelligent life on other planets, and they’ll be our friends, not our enemies. Together, we’ll work for the common good.’

Leonard Nimoy, I Am Spock, hypothesizing on why Star Trek found a place in the hearts of its fans, and why its fans would be so passionate about it.
(via cmdr-beverlycrusher-md)