That was rude about the toast though. I havent read far enough in the book to see what to do about rudeness
I think the idea is to change the subject and get on to a topic which leads to enthusiasm. Even if it's repetitive.
But of course, yes it's very hurtful, especially to your own child.
Having said that - your mother thought she was addressing her sister. She had misidentified you as her sister.
In her mind, she wasn't telling her daughter that she preferred her brother to her.
That doesn't let Mrs A (of Mapledurham) off the hook, though.
She was very rude about the toast.