There are two scenes were Mrs. Jennings is teasing Elinor about lovers left behind at Norland. Elinor is very uncomfortable and pained, but is composed outwardly.
However, Marianne was "vexed at it for her sister's sake, and turned her eyes towards Elinor, to see how she bore these attacks, with an earnestness which gave Elinor far more pain than could arise from such common-place raillery as Mrs. Jennings's." (end of chapter 7)
Then Marianne "felt for her most sincerely; but she did more harm than good to the cause, by turning very red, and saying in an angry manner to Margaret.." (end of chapter 12)
Through every re-read, I'm always bothered that Elinor didn't appreciate Marianne's emotional support for her pain. True, Marianne's emotions are overwrought and unwanted at times, but I would at least appreciate a sister that felt badly for you. Although I admire Elinor for being calm and controlled, her dislike of Marianne's open emotional reaction seems to be a little cold-hearted of her, and I don't like and support Elinor for feeling this way.