Any investment bought via credit always runs the risk of margin calls and, eventually, liquidation.

Any time you speak to people about their posture, you learn about their most recent investment activity. When someone just bought stocks, they tend to be bullish; someone who just sold is bearish.

In the investment business, you must expect to be wrong.

If you are not making any mistakes, you are being excessively risk-averse. Investing involves risk, and that means you will occasionally be wrong. And although it is okay to be wrong, it is not okay to stay wrong.

'Returnless risk' is not how you prepare for a decent retirement.

It is important for investors to understand what they do and don't know. Learn to recognize that you cannot possibly know what is going to happen in the future, and any investment plan that is dependent on accurately forecasting where markets will be next year is doomed to failure.