By fully understanding myself, I have greater understanding of humanity.

You have been, at some point, the person in a car park who spoke sharply to somebody who didn't deserve it.

There was a reason. It wasn't visible from outside.

That memory is the most useful thing you own for interpreting strangers. Everyone you meet is being driven by something you cannot see, and you happen to have detailed inside knowledge of what that is like.

People who insist they recognise themselves in nobody difficult tend to be the harshest judges. Charity comes out of the inventory, and the inventory has to include the unflattering entries.