If it's not a definite yes, it's a definite no.

In a world of seemingly infinite possibilities, how do you determine what to invest your time, energy and resources in? It is important that you invest wisely because there are a host of 2.5 star opportunities vying for your attention, but life is too short to waste time on them. Look for the 5 star opportunities.

The greatest investors on earth, though they diversify, do not waste their time diversifying among 2.5 star investments. Rather, they diversify but only among companies that promise the highest return. Warren Buffett of Berkshire Hathaway fame made a majority of his billions from investments in 10 companies. Not 1,000, nor 100... 10.

His words of advice when it came to choosing his investments?

If it’s not a definite yes, it’s a definite no.
— Warren Buffett