[banach]

The point is that you have a lot of influence over outcomes. There are mountains of evidence to support that fact, with comparatively easy and accessible interventions ranging from abstaining from smoking, to eating healthy food, to getting exercise. As with everything else in life, though, what you are doing by living healthily is turning the probabilities in your favor. That means that someone with unlucky genetic predispositions, or with an undiagnosed infection/deficiency/toxin exposure etc, might develop cancer despite doing everything in their power to avoid it, while a lucky bon-vivant smoker/drinker/junk foodie might just roll those dice favorably enough times to die of other causes. The point is that you should live your life based on the expected outcome of your actions, rather than on specific example cases, which may be outliers not representative of what you might expect if you follow their lead.