You have to know when to buy AND when to sell. I bought Netflix in 2010, but I sold it in 2011. I bought Amazon in 2006 and sold it a few months later. When

You have to know when to buy AND when to sell. I bought Netflix in 2010, but I sold it in 2011. I bought Amazon in 2006 and sold it a few months later. When the price doubles or triples, it's hard not to take the profits and run. That's why my best returns have all come from private equity, because it's locked up and I can't sell at the first dozen or so price points I would have wanted to.