"I began to understand how multiple factors drive profits at that company. Price movements showed me that the value of Exxon Mobile didn't have a simple relationship to the price of oil. It also responded to interest rates, the value of the US dollar, and especially economic expectations. I also learned more about the supply, demand, and cartel dynamics affecting the price of oil. I realized my knowledge of the oil business and the oil markets was way too shallow to make a call about oil company stock. I'd underestimated the long-term impact of factors driving oil prices down." Above is an excerpt from a book I have read some time ago (can't recall, but I think is this). When one decides to invest a substantial portion of his money into an asset or company, it should not be...