"These pages betray her secret; which is that she was naturally exuberant. And her power came, as all power comes, from the control and direction of that exuberance. . . . her original passion was a sort of joyous scorn and a fighting spirit against all that she regarded as morbid and lax and poisonously silly."--G.K. Chesterton, introduction to Love and Friendship.
I have been reading Jane Austen's Juvenilia recently. It has really made me reflect on the truth of Chesterton's idea. Jane Austen as naturally exuberant, and ridicules with more pointed silliness in the Juvenilia than in any of her novels. We can see some of this less restrained tone in Northanger Abbey, which makes sense since it was one of Jane's earlier novels, and one she did not revise after she wrote it. First Impressions and Elinor and Marianne were revised before their appearances as Pride and Prejudice and Sense and Sensibility, but NA was not.
As a reflection of Jane's exuberance, consider this passage from Lesley Castle:
She play'd, yet not even a pidgeon-pye of my making could obtain from her a single word of approbation. This was certainly enough to put any one in a Passion; however, I was as cool as a Cream-cheese and having formed my plan & concerted a scheme of Revenge; I was determined to let her have her own way & not even to make her a single reproach. My Scheme was to treat her as she treated me, and tho' she might even draw my own Picture or play Malbrook (which is the only tune I ever really like) not to say so much as "Thank you Eloisa"; tho' I had for many years constantly hollowed whenever she played, Bravo, Bravissimo, Encora, Da Capo, allegretto, con expressione, and Poco presto with many other such outlandish words, all of them, as Eloisa told me, expressive of my Admiration; and so indeed I suppose they are, as I see some of them in every Page of every Music book, being the Sentiments, I imagine, of the Composer.
I executed my Plan with great Punctuality; I can not say success, for Alas! my silence while she played seemed not in the least to displease her; on the contrary, she actually said to me one day "Well Charlotte, I am very glad to find that you have at last left off that ridiculous custom of applauding my Execution on the Harpsichord till you made my head ake, & yourself hoarse. I feel very much obliged to you for keeping your Admiration to yourself."