Sense and Sensibility
How we cite our quotes:
Lucy went on. "I am rather of a jealous temper, too, by nature, and from our different situations in life, from his being so much more in the world than me, and our continual separation, I was enough inclined for suspicion, to have found out the truth in an instant, if there had been the slightest alteration in his behaviour to me when we met, or any lowness of spirits that I could not account for, or if he had talked more of one lady than another, or seemed in any respect less happy at Longstaple than he used to be. I do not mean to say that I am particularly observant or quick-sighted in general, but in such a case I am sure I could not be deceived." (24.6)
Lucy issues a clear warning to Elinor here – back off, sister!
On Elinor its effect was very different. She began immediately to determine that Edward, who lived with his mother, must be asked, as his mother was, to a party given by his sister; and to see him for the first time after all that [had] passed, in the company of Lucy! -- she hardly knew how she could bear it!
These apprehensions perhaps were not founded entirely on reason, and certainly not at all on truth. They were relieved however, not by her own recollection, but by the good will of Lucy, who believed herself to be inflicting a severe disappointment when she told her that Edward certainly would not be in Harley Street on Tuesday, and even hoped to be carrying the pain still farther by persuading her, that he was kept away by that extreme affection for herself, which he could not conceal when they were together. (34.10-11)
Lucy, apparently, simply can't resist the urge to twist the knife at every possible opportunity. Elinor, in order to keep within the bounds of social convention, has no choice but to simply keep taking it.
"Perhaps, Miss Marianne," cried Lucy, eager to take some revenge on her, "you think young men never stand upon engagements, if they have no mind to keep them, little as well as great." (35.27)
Ooh, ouch. That's a low blow on Lucy's part – she's starting to take her jealousy out on Marianne as well as Elinor, with this personal jab at Marianne's breakup with Willoughby.