Quote 1
"My judgment," he returned, "is all on your side of the question; but I am afraid my practice is much more on your sister's. I never wish to offend, but I am so foolishly shy, that I often seem negligent, when I am only kept back by my natural awkwardness. I have frequently thought that I must have been intended by nature to be fond of low company, I am so little at my ease among strangers of gentility!" (17.6)
Edward feels himself to be at odds with high society, and can't ever get himself to fit in. This is yet another sign that he's not cut out for the dazzling career his mother envisions for him…but when will he be able to set out on his own path?
Quote 2
"You have no ambition, I well know. Your wishes are all moderate."
"As moderate as those of the rest of the world, I believe. I wish, as well as everybody else, to be perfectly happy; but, like everybody else, it must be in my own way. Greatness will not make me so." (17.2)
Good old Edward. His sole ambition is to get out from under his family's pressure and make his own way – and in so doing, find his own particular kind of happiness.
Quote 3
Edward made no answer; but when she had turned away her head, gave her a look so serious, so earnest, so uncheerful, as seemed to say, that he might hereafter wish the distance between the parsonage and the mansion-house much greater. (40.16)
This is a rather odd reaction to the news that someone (namely Colonel Brandon) has come along out of the blue and saved one's future from ruin. However, it's the best reaction Edward can come up with – might he be jealous of the relationship between Elinor and the Colonel?