PARASITES AND PREDATORS: “Predators want to kill you and eat you right there on the veldt. Parasites, by contrast, want to keep you alive, the better to serve as a parasite paradise, a cozy haven where they can grow at their own pace, suckle on your moist, nourishing tissues, multiply their numbers and finally, one way or another, pass those numbers along.” Kinda like the difference between, say, terrorists and lobbyists.