In movies/cartoons you see astronauts and people in spaceships opening doors and closing them again with no suits on. Is it possible in "real life" or would you die immediately? Because consider this:
If we built some giant space colony/living facility (like in Star Trek), isn't there always the danger of someone opening a way outside from which you could die instantly if no one is in a spacesuit (if true?)?
What about the fear of being in closed, confined spaces too long? Some people may panic and even kill themselves/others or become destructive in chaos from being trapped in an enclosed space colony.
Obviously an alternative to the long-winded process of terraforming other planets is to create safe ships to fly around in and live in. And future technology could prove this to be better than terraforming since a spaceship is magnitudes more versatile and easier to self-sustain and maintain than a gigantic planet.