I will be a friend to him, as his father was a friend to me

Kindness is taken in the wrong way

And David said, I will be a friend to Hanun, the son of Nahash, as his father was a friend to me. So David sent his servants, to give him words of comfort on account of his father. And David’s servants came into the land of the children of Ammon.
2 Samuel 10:2

But the chiefs of the children of Ammon said to Hanun their lord, Does it seem to you that David is honouring your father by sending comforters to you? has he not sent his servants to go through the town and make secret observation of it, and overcome it?
2 Samuel 10:3