Aunt Alexandra does seem to have a way of ruining Scout's appetite, in spite of her aunt's reputation of being an excellent cook. At the Finch family Christmas dinner, Alexandra forces Scout to sit at the children's table with the dreaded Cousin Francis.
I often wondered what she thought I'd do, get up and throw something? (Chapter 9)
Aunt Alexandra could even ruin Scout's chance to simply get a glass of water.
When I appeared in the doorway, Aunty would look as if she regretted her request; I was usually mud-splashed or covered with sand. (Chapter 13)
On the morning after the children had come to Atticus's rescue at the jail,
Everybody's appetite was delicate this morning... Aunt Alexandra sipped coffee and radiated waves of disapproval. (Chapter 16)
After finding out that the children had watched the trial of Tom Robinson without permission, the children came home for dinner--with Atticus's approval to return to the courthouse afterward.
Aunt Alexandra met us and nearly fainted... She just rearranged food on her plate, looking at it sadly... (Chapter 21)
Scout is entirely out of her element at the Missionary Circle tea: She is invited to attend because it is part of her aunt's "campaign to teach me to be a lady." Although Alexandra isn't to blame, the ladies make jokes at Scout's expense, and she knows they meant to
... trap you with innocent questions to make fun of you... (Chapter 24)