Many times people get talking to a friend and start depending on his judgment regarding investments. It is one of the most common mistakes that is oft repeated by people leading about the losses. One should be cautious enough in not investing in businesses that one doesn’t understand. One should not buy stock in companies if one does not understand the business model of those companies. The best remedy would be to have a diversified portfolio, mutual funds. If someone wants to invest in individual stocks then it is important for him/her to understand each company those stocks represent.