The more cash that builds up in the treasury, the greater the pressure to piss it away.

There's no use diversifying into unknown companies just for the sake of diversity. A foolish diversity is the hobgoblin of small investors. That said, it isn't safe to own just one stock, because in spite of your best efforts, the one you choose might be the victim of unforeseen circumstances. In small portfolios, I'd be comfortable owning between three and ten stocks.

I think you have to learn that there's a company behind every stock, and that there's only one real reason why stocks go up. Companies go from doing poorly to doing well or small companies grow to large companies.

There seems to be an unwritten rule on Wall Street: If you don't understand it, then put your life savings into it. Shun the enterprise around the corner, which can at least be observed, and seek out the one that manufactures an incomprehensible product.

In the long run, a portfolio of well chosen stocks and/or equity mutual funds will always outperform a portfolio of bonds or a money-market account. In the long run, a portfolio of poorly chosen stocks won't outperform the money left under the mattress.

All the math you need in the stock market you get in the fourth grade.

That's not to say there's no such thing as an overvalued market, but there's no point worrying about it.