The NASDAQ index fell by over 11% from peak to trough recently. If you were thinking of picking up some stocks on the cheap, you might be on the hunt now. But first, you have to find the right companies to buy. Even then, it’s not enough. Anyone can find good stocks. Buying it takes just a few taps on your smartphone. But not everyone has the tenacity to hold on to a good stock for the long term. The reason? Because it’s not easy. It’s hard. How hard? Well, even the best-performing stocks over the last decade have undergone periods of time when their stock prices go into a tailspin. And we are not talking about minor, single-digit percentage declines, mind you. We are talking about stomach-churning stock dives. Take Netflix (NASDAQ: NFLX). I have owned shares of the online streaming giant since January 2007....