Without trying to sound too philosophical over this one, it's a matter of someone's innate or cultivated level of awareness. I mention "innate", since there are even small kids who already surprise you with their power of observation. I don't think it has much to do with someone's I.Q., because there are many educated folks who miserably fail in their lives.
So, it's all about awareness, which might as well be a "mother" of wisdom. To some folks it comes naturally to be and to stay aware of what life is all about, what they want from it, and how not to sabotage what they want by wasting time and energy in soap operas of their own make.
Now you can start calling me philosophical, if you wish : God, or universal intelligence loves variety; and since the whole material world is composed of some over hundred different chemical elements, people are following it with an analogy of their own garden variety of mentalities, which together compose our collective reality as we know it. Someone before me has already said : "It takes all kinds" - so, what comes natural to some individuals may be a superhuman impossibility to some other. This includes how they arrange their mind-styles and life styles.