When I was an undergraduate studying finance, the idea of buying and selling common stocks sounded thrilling. It captivated me. I read accounts of day traders making millions, supposedly, by just sitting at their computers and buying low and selling high. How easy does that sound!? All I needed was a handful of well-placed trades each day and I was sure to be retired by age 30. Yet, as I delved deeper into the world of finance, and subsequently began my career as a professional portfolio manager, I learned those day trading stories were far from the reality of successful long-term investing.