"In the long run, the only sustainable source of competitive advantage is your ability to learn faster than your competition."
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!"
When you are young spend at least 6 months to one year living as poor as you can, owning as little as you possibly can, eating beans and rice in a tiny room or tent, to experience what your “worst” lifestyle might be. That way any time you have to risk something in the future you won’t be afraid of the worst case scenario.
"Books can be mirrors, windows, and sliding glass doors."
"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'"