Some advocates of "social justice" would argue that what is fundamentally unjust is that one person is born into circumstances that make that person's chances in life radically different from the chances that others have – through no fault of one and through no merit of the others.
Maybe the person who wasted educational opportunities and developed self-destructive behavior would have turned out differently if born into a different home or a different community.
That would of course be more just. But now we are no longer talking about "social" justice, unless we believe that it is all society's fault that different families and communities have different values and priorities – and that society can "solve" that "problem."
Nor can poverty or poor education explain such differences. There are individuals who were raised by parents who were both poor and poorly educated, but who pushed their children to get the education that the parents themselves never had. Many individuals and groups would not be where they are today without that.
All kinds of chance encounters – with particular people, information or circumstances – have marked turning points in many individual's lives, whether toward fulfillment or ruin.