[raincom]

Life is a random walk. Doing well on some random point just opens up more future sub-trees at that point. Doing not so-well at some point means you have less opportunities at that moment; as you chug long, you may step on another point, which can lead to a great success. This doesn't mean that one should treat one's life haphazardly matter (come what may); learn from earlier generations, others' lives, from one's own past, and navigate life without a large variation (or standard deviation)

Some points (say, set X) are impossible to reach, because one doesn't end up on a point that reaches X. For instance, MBB consulting recruits students from elite Ivy League. Usually, MBB alumni moves to F100 companies laterally, thereby reaching C-levels faster. You can read posts on collegeconfidential dot com, how some students plan a course of action when they were in middle school to get into million dollars per annum jobs. The chance of success is higher if one traverses the well-trodden path, that's why there is a rat race.