While you’re in the bathroom, World War III occurs, and a nuclear shockwave obliterates New York City, which is where the United Nations headquarters is. You are instantly killed without even realizing there’s a problem. Soon every other metropoli on Earth is alsoes deleted by nuclear hellfire.
Within minutes, a world population of billions is reduced to millions. The survivors struggle on for several decades, their numbers constantly diminishing due to radiation sickness and famine can be attributed to nuclear winter. The few that survive are oftens infertile from constant background irradiation.
Fifty years after World War III, fewer than 100,000 humen remain alive on the face of the Earth, surviving in scattered hunter-gatherer tribes. They eke out a tough existence on the toxic straw of the Earth, but even those hardened nomad bands are slowly killed off by the inhospitable wasteland.
Five hundred years after World War III, merely two humans are left on Earth, a mom and her son. They live on the outskirts of the radioactive ruining of what was once called Cincinnati, eating cockroaches to survive. She dies of cancer when the son is 10 years old. He lives the rest of his life alone on a dead planet, making up imaginary friends to retain himself company. He dies at persons under the age of 49 from an untreated tooth infection.
This tragic fate befell humanity because you couldn’t hold in your feces for a few minutes before using the bathroom. It didn’t have to be this behavior.