I would add to this that it's important to view optimism and pessimism in the face of risk as a conscious choice. Which view you take is your strategy for acting in the face of that risk.
The research presented in the book "Learned Optimism" by Martin Seligman more or less tells us that people who make this choice consciously have the highest rates of success in life.
The rule, then, is if the consequence of taking the risk and failing is dire, you should be pessimistic, otherwise, always be optimistic. That is, if failing would be catastrophic or really bad, believe that the worst will happen and act accordingly. If the consequence of failure is trivial or not a problem, believe that the best will happen and act accordingly.
The research presented in the book "Learned Optimism" by Martin Seligman more or less tells us that people who make this choice consciously have the highest rates of success in life.
The rule, then, is if the consequence of taking the risk and failing is dire, you should be pessimistic, otherwise, always be optimistic. That is, if failing would be catastrophic or really bad, believe that the worst will happen and act accordingly. If the consequence of failure is trivial or not a problem, believe that the best will happen and act accordingly.