Just think of Warren Buffet's philosophy, quoted by Mary Buffet and David Clark in The Tao of Warren Buffet, "You only have to do a few things right in your life, so long as you don't do too many things wrong." The authors continue, "Warren decided early in his career it would be impossible for him to make hundreds of right investment decisions, so he decided that he would invest only in the business that he was absolutely sure of, and then bet heavily on them. He owes 90% of his wealth to just ten investments. Sometimes what you don't do is just as important as what you do."

What's strange is that as he got older, he got more defocused.

He always said he didn't invest in technology because he didn't understand the business.

Now he invests in technology. Are we to believe he understands those businesses now?