The closet full of shelves made me laugh too, and another line in Letter 18 reminded me of P&P:

Whenever I fall into misfortune, how many jokes it ought to furnish my acquaintance in general, or I shall die dreadfully in their debt for entertainment.

Doesn't this remind you of Mr. Bennet's "For what do we live, but to make sport for our neighbours, and laugh at them in our turn"? It's so much fun finding examples of JA giving her characters her own opinions and attitudes (and seeing where she doesn't, as well)!