Boring businesses often produce wonderful investment results.Over the long term, there are fewer tools that investors have that can build wealth quite like the stock market. The S&P 500, for example, has done a wonderful job of bringing investors financial independence. But some businesses have performed even better than the broader market.Take Procter & Gamble (PG 0.49%). In the past 40 years, this consumer staples stock has produced a total return, including dividends, of 14,810%. That means a $10,000 inv ...