John D. Arnold

"Once I make $15 million, if I’m still trading, punch me in the face."

"John understood perfectly well that at a certain point it makes a lot more sense to spend money doing the things you love than to simply earn more money—but his numerical target kept shifting. He didn’t quit when he’d amassed $15 million. He was trading so well that the $15 million became $25 million, which eventually became $100 million, and so on. When you’re on a winning streak that big, it’s hard to stop, even when your rational mind tells you that you should."