I love Emma's initial reaction to Mrs Elton - she is infuriated at her presumption of calling Mr Knightley 'Knightley' and then a little later believes that Frank was the first person she thought of...

"Insufferable woman!" was her immediate exclamation. "Worse than I had supposed. Absolutely insufferable! Knightley! I could not have believed it. Knightley! never seen him in her life before, and call him Knightley! and discover that he is a gentleman! A little upstart, vulgar being, with her Mr. E., and her caro sposo, and her resources, and all her airs of pert pretension and under-bred finery. Actually to discover that Mr. Knightley is a gentleman! I doubt whether he will return the compliment, and discover her to be a lady. I could not have believed it! And to propose that she and I should unite to form a musical club! One would fancy we were bosom friends! And Mrs. Weston! Astonished that the person who had brought me up should be a gentlewoman! Worse and worse. I never met with her equal. Much beyond my hopes. Harriet is disgraced by any comparison. Oh! what would Frank Churchill say to her, if he were here? How angry and how diverted he would be! Ah! there I am thinking of him directly. Always the first person to be thought of! How I catch myself out! Frank Churchill comes as regularly into my mind! "