I recently picked a new primary care physician.  After two visits and exhaustive lab tests, he said I was doing "fairly well" for my age.  A little concerned about that comment, I couldn't resist asking him, "Do you think I'll live to be 80?"

He asked, "Well, do you smoke tobacco or drink beer?"

"Oh no," I replied, "I've never done either."

Then he asked, "Do you eat rib-eye steaks and barbecued ribs?"

I said, "No, I've heard that all 'red meat' is very unhealthy!"

"Do you spend a lot of time in the sun, like playing golf?" he asked.

"No I don't," I said.

He said, "Do you gamble or drive fast cars?" 

"No," I said, "I've never done any of those things."

He looked at me and said, "Then why on earth do you want to live to be 80?"