The presence of risk does not make something a gamble, else all of life would be a gamble, and God would be like Donald Trump. It is not so. How you view the reality of risk (as entertainment or, on the other extreme, as a condition to be mastered) pretty much determines what the odds are of your success. Someone said, 'if you have a positive expectancy, you're like the house, if not, you're the sucker,[paraphrase]' is a great way to say it. Another way of putting it is this: brain surgery might be risky for you (owing to a presumed lack of experience) but not for your favorite brain surgeon. Your preparation for the risk at hand has a large influence on the probability of a successful outcome. Even for the best prepared, however, there exists the possibility of unforseen or forseen setbacks. On any single event, there is some element of uncertainty no matter how well prepared you are. The more the event is repeated, assuming you have that positive expectancy, the effect of this uncertainty regarding forseen setbacks diminishes (never to zero though.) The risk of the unforseen is constant.