A REALLY annoying term and storyline used way too much in movies and television shows. The comment itself sounds absolutely stupid, and is commenly used for one person (i.e. Buffy the vampire slayer) which makes it hard to believe that one person could do the job on their own. Even when they get help from others, considering that there are 6 billion people on the planet and considering the size of "the world," it makes it too radical of an idea to actually be interesting. Even when the storyline IS good, it's still a stupid term to use.
Ice cream man: You want me to walk off of my job?! What am I supposed to do for you and your company?
CIA dude: Save the world.