Our thoughts really do create our lives. They've done a lot of research showing if you're an optimistic, positive person you will be a healthier person than if you're a sad, depressed, negative person.
If you have a great deal of knowledge, but you're governed by negative emotions, then you tend to use your knowledge in negative ways. Therefore, while you are learning, don't forget the importance of warmheartedness.
There is one thing of which I can assure you. If good performance of the fund is even a minor objective, any portfolio encompassing one hundred stocks (whether the manager is handling one thousand dollars or one billion dollars) is not being operated logically. The addition of the one hundredth stock simply can't reduce the potential variance in portfolio performance sufficiently to compensate for the negative effect its inclusion has on the overall portfolio expectation.