It's not unusual for investors to get greedy and chase returns, often to their detriment.
"Once a stock or new investment vehicle starts moving, it's tempting to jump on board," Luxenberg says. "Your friends and family are all making great money at it. Why not you?"
Unfortunately, most people wait until the trend is well-established before they plunge in.
"Most investors buy the right things but do it at the wrong time, and that's enough to sink a portfolio," he says.