Only when you’re comfortable enough to be able to handle the short-term can you figure out how to utilize the long-term to your advantage.
A large part of managing money is managing a client's risk. Ben nails it. In my opinion the biggest predictor of a portfolio's long term success or failure is the management of the short term expectations. If a client expects their portfolio to never dip by 10% then you have some work to do in managing their expectations. There is a reason why the amusement park lines are the longest for the newest, biggest, fastest rides. Most people would love to average 10%. But, not ever investor is willing to ride the roller coaster. Some are better suited for the Tilt-A-Whirl or the spinning teacups.