Work hard and control the ego as an investor

There are two kinds of people who lose money: those who know nothing and this who know everything. 
-Henry Kaufman 

To be a good investor, you have to make sure that you are not the weakest person at the table. Smarts is required to do well and understand the risks, but those who know everything will also never be successful. They cannot think in terms of probability and the fact that bad things can happen to even the best investment idea. We are always facing uncertainty.