Perhaps the best (and possibly only) example of this comes during the missionary circle tea in Chapter 24. Scout is never happy about having to exhibit any ladylike ways, but she tries her best at the church gathering. She wears her best Sunday dress and a petticoat, and she bites her tongue when Miss Stephanie makes a joke at her expense. Although much of the conversation is over her head, Scout understands enough to come away with a less-than-satisfactory final impression of many of the women. Following Atticus' news of Tom's death, both Miss Maudie and Aunt Alexandra regain their composure and continue serving the ladies as if nothing had happened. This does impress Scout, who politely asks Mrs. Merriweather--who had earlier drawn the ire of Miss Maudie--if she would like a cookie, too.
After all, if Aunty could be a lady at a time like this, so could I.