I have attended a few symposium on entrepreneurship, when the topic of entrepreneur character or personality is discussed - there are lots of different opinion but one of the popular and common one is the "propensity for risk taking".
Here's what Peter Drucker says:
"I know a good many successful entrepreneurs. Not one of them has a propensity for risk taking. Most successful innovators in real life are colorless figures, and much more likely to spend hours on cash-flow projections than to dash off looking for risks. They are not risk-focused, they are opportunity-focused."