Some people destroyed their health, yet they rarely did this through deliberate intention. They did it because they lacked foresight, because they were careless, impatient, and irresponsible. There were enormous numbers of medically careless people in the world. There had once been titanic, earth-shattering numbers of such people, but hygienically careless people had died in their billions during the plagues of the 2030s and 2040s. The survivors were a permanently cautious and foresightful lot. Careless people had become a declining interest group with a shrinking demographic share.