As a kid, I spent my summers with my grandparents on their ranch in Texas. I helped fix windmills, vaccinate cattle, and do other chores. We also watched soap operas every afternoon, especially "Days of our Lives." My grandparents belonged to a Caravan Club, a group of Airstream trailer owners who travel together around the U.S. and Canada. And every few summers, we'd join the caravan. We'd hitch up the Airstream trailer to my grandfather's car, and off we'd go, in a line with 300 other Airstream adventurers.

I loved and worshipped my grandparents and I really looked forward to these trips. On one particular trip, I was about 10 years old. I was rolling around in the big bench seat in the back of the car. My grandfather was driving. And my grandmother had the passenger seat. She smoked throughout these trips, and I hated the smell.

At that age, I'd take any excuse to make estimates and do minor arithmetic. I'd calculate our gas mileage -- figure out useless statistics on things like grocery spending. I'd been hearing an ad campaign about smoking. I can't remember the details, but basically the ad said, every puff of a cigarette takes some number of minutes off of your life: I think it might have been two minutes per puff. At any rate, I decided to do the math for my grandmother. I estimated the number of cigarettes per days, estimated the number of puffs per cigarette and so on. When I was satisfied that I'd come up with a reasonable number, I poked my head into the front of the car, tapped my grandmother on the shoulder, and proudly proclaimed, "At two minutes per puff, you've taken nine years off your life!"