Every lunch hour Dave picked up a can of dog food at the grocery store, went across the street to a park bench, and ate the whole can with evident gusto. A doctor who happened to pass through the park regularly couldn’t help noticing Dave’s behavior and finally decided to offer some advice. “I’m an internist,” he explained, “and I think you should know that stuff isn’t a very healthy diet for a human In fact, eating it could kill you.”
“Thanks for the advice, Doc,” said Dave, wolfing down another forkful, “but I’ve been eating it for years now and I feel just fine.”
The doctor shrugged and walked off. A few months later he noticed Dave was missing from his bench, and after a while he asked another park regular what had happened.
The doctor shook his head. “I told him that dog food would kill him.”
“It wasn’t the dog food that did it,” the fellow reported. “He got run over while chasing a car.”