I'm reading a marvelous 80+ year old book called Where are the Customers' Yachts? that has gone through several reprints and long served as a warning against the "kindergarten" that is Wall Street. Written in an almost satire-like tone, there is a great section in the third half of the book that asks each would-be investor to pose six questions to themselves and answer them correctly. If he's unable to answer "yes", or has to hesitate, then he should count the answer wrong.

Here's what the author has to say ...

1. Do you perceive quite clearly what is the objection to playing a roulette wheel that has two zeros on it? (If not, don't bother to be a financier; be a roulette player.)

2. If a man has tossed a coin "heads" four times in succession, which do you think he is more likely to toss the fifth time, heads or tails? (If you think he is more likely to toss either heads or tails, look into the interior-decorating game. You have that instinctive type of mentality which might do very well at that.)

3. When do you consider that it is a good purchase to draw one card to an insight straight? (Answer - when you are playing for soybeans.)

4. If you have answered #3 correctly, do you find that when you are actually playing poker for money, you can always resist making that draw? (If not, stay home with your money and start practicing being a miser.)

5. If a stock which is not paying any dividend is split two for one, how much good does that do the stockholder? (If you think it does him any real good, come down and join our sales department but steer clear of our trading department.)

6. What is the primary purpose of a business enterprise? This questions is specifically for young men considering entering the banking field, where they will have a constant parade of business propositions passing before them, and they will be required to plump for a few of them and say "no" to the others. The answer is elementary and obvious: the primary purpose of a business is to make money. Almost anyone knows this with the top part of his brain. But there are only a few valuable young men who also know this all up and down their spinal column. Most businessmen imagine that they are in business to make money, and that this is their chief reason for being in business, but more often than not they are gently kidding themselves. There are so many other things which are actually more attractive. Some of them are: to make a fine product or to render a remarkable service, to give employment to revolutionize an industry, to make oneself famous, or at least to supply oneself with material for conversation in the evening. I have observed businessmen whose chief pre-occupation was to try to prove conclusively to their competitors that they themselves were smart and that their competitors were damn fools - an effort which gives a certain amount of mental satisfaction but no money at all. I have even seen some whose chief interest lay in proving this point to their partners. So give yourself a real good mark if you know that a business should make money, but only if you really know it.

Had investors heeded this simple advice, the credit crisis wouldn't have happened, the dot-com bust wouldn't have occurred, the Nifty Fifty wouldn't have done so much damage to a generation of investors; you get the idea.