Miss Austen on rapid motion.

"It may be possible to do without dancing entirely. Instances have been known of young people passing many, many months successively without being at any ball of any description, and no material injury accrue either to body or mind; but when a beginning is made--when the felicities of rapid motion have once been, though slightly, felt--it must be a very heavy set that does not ask for more."

I'm not sure why I love this paragraph so; it's not one of Austen's more subtle lines; maybe it's the image it gives me of young persons of her era pinging off each other like water molecules approaching boiling...