At the tea party, for what is it that Aunty was silently thanking Miss Maudie? Harper Lee's To Kill a Mockingbird
Mrs. Merriweather, "a faithful Methodist under duress," is a self-righteous, sanctimonious hypocrite. Not only this, but she is inconsiderate of her hostess when she tells Gertrude,
"I tell you there are some good but misguided people in this town. Good, but misguided."
She continues by saying that some thought they were doing the right thing, but all they did was "stir 'em up," meaning the black community. She, then, goes on to say that her maid Sophy, who she keeps on as an employee out of the goodness of her heart, has had the effrontery to be "sulky." In a remark that suggests the hypocrisy of the Merriweathers, Miss Maudie asks her if her husband's food does not stick going down, meaning that they eat the food of this maid whom they consider so inferior.
"Maudie, I'm sure I don't know what you mean," said Mrs. Merriweather.
"I'm sure you do," Miss Maudie said shortly [curtly].
Aunt Alexandra, who looks at her with "a look of pure gratitude," appreciates Miss Maudie's criticism of Mrs. Merriweather's disparaging remarks about her brother, Atticus Finch, and his defense of Tom Robinson.