When someone is mean to us without good cause, pushes us away cruelly in love, or bullies us at work, gossips about our children, or steals our money, we are in pain, of course.
But also, to a vexing extent, we are reduced to dire puzzlement.
Why on earth did this happen?
Why is someone like this?
What's up with human nature?
The questions add a whole new layer of suffering.
It's to assuage these haunting questions that we can turn to a simple-sounding dictum: All cruelty is, in the end, inherited.
The meanness that we witness around us in the here and now, in the shops, in boardrooms, in bedrooms, and online forums, is always, by a law of psychological economy, something that's been, with appalling diligence, passed down from one person to another.
The ugliness that washes up on our doorsteps today will be a legacy of ill-treatment, violence, selfishness, hard-heartedness, cynicism, and indifference that came, somewhere offstage, from an angry father or a vindictive mother, a rageful great-aunt or a sexually abusive uncle, who themselves were handed the corruption by a perverted grandfather or alcoholic grandmother, all the way up the generations to our earliest ancestors in the Rift Valley or the Garden of Eden.
We can look out across our world for these complex chains of inheritance.