I was accused of being a liar

yesterday. 
I don't think the person who did it actually realised what she was doing. She was too busy concentrating on defending  her own actions.  Her rather "over the top" reaction to something she didn't like was to demand to know who was saying it and say "I'm going to check on that". When she does "check" she will make a fool of herself.  I can't stop her.
It made me wonder about adults who argue. I get along with 99% of the world. I can count on the fingers of one hand the number of people I have not managed to have some sort of at least reasonably civil relationship with - and have some fingers left over.  Perhaps I just don't know enough people - or I don't know them well enough. I grew up in a family where, although there was tension at times, actual arguments were rare. The Senior Cat is one of the most peaceful, even tempered people I know.  Yes, he can get irritated but for him to get really angry is so rare the occasions have been passed down  in the family's oral history. 
The Whirlwind's father is rather the same. At his place of work he has a reputation for being the man with whom they can't argue. 
"You just can't argue with him. It's not that he agrees with you or anything but he just doesn't let argument happen. It's really annoying when all you want is a good bust up," one of his colleagues once told me. He was clearly frustrated.
On the few occasions I have found myself at the scene of an argument taking place in another family all I have wanted to do is prowl off rapidly. I squirm with embarrassment. It's intruding on something I should not be intruding on. 
Perhaps I should have said something yesterday but we were talking in a very public space and someone was standing close enough to hear every word which was  being said. I didn't want an outsize row which would embarrass everyone.
Still perhaps it would have helped to clear the air. I just hope she doesn't make matters worse for herself.