Quote 1
"My objection is this; though I think very well of Mrs. Jennings' heart, she is not a woman whose society can afford us pleasure, or whose protection will give us consequence." (25.7)
After Elinor's continued defense of Mrs. Jennings, we're a little surprised at the line of argument she takes here to try and avoid going to London. Despite the fact that she cares most about people's personalities, she demonstrates her simultaneous interest in social status and advantage.
Quote 2
"I am afraid," replied Elinor, "that the pleasantness of an employment does not always evince its propriety."
"On the contrary, nothing can be a stronger proof of it, Elinor; for if there had been any real impropriety in what I did, I should have been sensible of it at the time, for we always know when we are acting wrong, and with such a conviction I could have had no pleasure." (13.19)
This spat between Elinor and Marianne demonstrates their differing views on society, and how much control it should have over our actions. Marianne seems to believe that we should really just do what we feel like doing, whereas Elinor always thinks of the social ramifications of any action.
Quote 3
"But I did not love only him; -- and while the comfort of others was dear to me, I was glad to spare them from knowing how much I felt. Now, I can think and speak of it with little emotion. I would not have you suffer on my account; for I assure you I no longer suffer materially myself. I have many things to support me. I am not conscious of having provoked the disappointment by any imprudence of my own, and I have borne it as much as possible without spreading it farther. I acquit Edward of all essential misconduct. I wish him very happy; and I am so sure of his always doing his duty, that though now he may harbour some regret, in the end he must become so. Lucy does not want sense, and that is the foundation on which everything good may be built. And after all, Marianne, after all that is bewitching in the idea of a single and constant attachment, and all that can be said of one's happiness depending entirely on any particular person, it is not meant -- it is not fit -- it is not possible that it should be so. Edward will marry Lucy; he will marry a woman superior in person and understanding to half her sex; and time and habit will teach him to forget that he ever thought another superior to her." (37.13)
Elinor's approach to love comes out clearly here – she claims that she's basically reasoned her way out of sorrow (which we know not to be true). She attempts to conquer love and heartbreak with logic.