[WP] a zombie apocalypse occurs, the weak and inadequate are killed, but 500 years later the natural selection of the apocalypse leaves only the strongest and brightest to breed and rebuild. Everyone is the best of the best.
"Welcome everyone to the 500 anniversary of a zombie apocalypse celebration party! Today we celebrate the biggest tragedy in the history of humanity, that has also turned out to be our greatest fortune. Just in 28 days all of the humanity's problems were solved. Global warming, starvation, lack of energy and resources, all wars and conflicts. All thanks to the unnamed hero, the mad biohacker, who, using his home-grown, genetically modified virus, did what the rest of our ancestors never had the balls to do - wipe out 98% of living humans.
Only the richest, smartest, toughest and healthiest humans were left, now free to rebuild the human civilization from scratch, never to repeat the mistakes of our ancestors. Without all the dead(walking-dead, ha-ha) weight, the speed of the scientific progress increased by 1000% and has been steadily growing ever since. With no weak, poor, and stupid to stand in our way, and with a common enemy to defeat, we had a purpose and a reason to abandon all the stupid arguments, and get together, solving humanity's common problems.
Even the racism and all kinds of inequality were defeated. Once everybody had zombies to hate, all the quarrels between the living humans immediately became insignificant.
With the abundance of space and resources, and nothing to hold us back, zombies didn't seem like such a huge problem. It took us only 3 years to get it together enough to start colonizing and terraforming Mars.
So rejoice, my friends. Let's get onto our spaceships, return to the Old Earth, and celebrate that nameless hero by participating in our annual zombie-hunt ceremony. Happy Apocalypse-Day, everybody!"