It was curious

I came across this in The No. 1 Ladies' Detective Agency, the charming novel by Alexander McCall Smith. His heroine, Mma Precious Ramotswe muses:
"It was curious how some people had a highly developed sense of guilt... while others had none. Some people would agonise over minor slips or mistakes on their part, while others would feel quite unmoved by their own gross acts of betrayal or dishonesty."
It's a naive comment. Of course, some people have no sense of guilt. You couldn't have war, atrocities, rapes, murders and torture without people who don't feel guilt. That shouldn’t need saying… but it does.

I’m thinking now not of those horrific things, or the people who do them, but of ordinary people. Just plodding citizens, like you and me, trying to have a decent go at it. Isn’t it odd how so many people aren’t concerned about being fair? How they will take and take till someone stands up and makes a point of it? Behaviour essentially guided by how much they can get away with. No internal checks at all! No innate sense of justice, or even concern for other people.

Takers are even more common than murderers. And to exclaim about them is naiver still.