When it comes to seeming magnanimous, people prefer to be on equal footing, if not greater, than the party they are with.

While the lady had indeed sent me an angry letter, for a small mistake of mine... it had been a few days already; she had simmered down.

So when I met her now, I didn't yell at her. I apologized and sympathized with her point of view, so soon, she began apologizing and sympathizing with my point of view.