I know it's been done before but a deserted apocalypse..
...would be so nice. Just a few thousand people all over the world. As long as there are some really hot guys who cares. Species are supposed to be kept in check by population decreases due to disease, fighting and so on. So it is wrong to want to fight every disease. Huge numbers of the population should be dying so we don't overpopulate and become really immoral with power. Smaller groups are better for everyone. And it would help the socially anxious.