How does Ibsen make this conversation between Hedda and Brack so memorable?

HENRIK IBSEN: Hedda Gabler, Read this extract, and then answer the question that follows it:

Hedda: I’d really danced myself tired, my dear sir. I had had my day … [She gives a little shudder.] Oh, no … I’m not going to say that. Nor think it, either.

Brack: With respect, madam, you’ve no reason to.

Hedda: Oh … reason… . [She sums him up with her look.] And Jörgen Tesman … you must allow that he’s a most worthy person in every way.

Brack: Oh, solid worth. Heaven preserve us.

Hedda: And I can’t see that there’s anything specifically ridiculous about him. … Or what do you say?

Brack: Ridiculous? No-o … I wouldn’t say that exactly… .

Hedda: Well. But then he’s a most diligent research worker, at any rate! … And after all, he might get somewhere with it in time, in spite of everything. Brack [looks at her a little uncertainly ]: But I thought you believed, like everybody else, that he’d make a really outstanding man. Hedda [with a tired expression]: Yes, so I did. … And then when he came along and was so pathetically eager to be allowed to support me. … I don’t really see why I shouldn’t let him?

Brack: Well of course, if you put it like that… .

Hedda: It was more than any of my other gallant friends were prepared to do, dear Mr. Brack. Brack [laughs]: Ah, I regret I can’t answer for all the others. But as for myself, as you know I’ve always observed a … a certain respect for the bonds of holy matrimony. In a general sort of way, my lady. Hedda [banteringly ]: Well no, I never really had any very high hopes of you.

Brack: I demand no more than a nice intimate circle of acquaintances, where I can rally round with advice and assistance, and where I’m allowed to come and go as … as a trusted friend… .

Hedda: Of the master of the house, you mean? Brack [inclines his head]: Candidly … of the lady, for choice. But naturally of the man as well. D’you know … this sort of … let me put it, this sort of triangular relationship … it’s really highly convenient for all concerned.

Hedda: Yes, I’d have been glad of a third on the trip, often enough. Ugh … sitting there, just two people alone in the compartment … !

Brack: Fortunately, the nuptial journey is at an end… . Hedda [shakes her head]: The journey’ll be a long one … a long one yet. I’ve just come to a stopping-place on the line. Brack: Well, then you jump out. And move around a little, my lady.

Hedda: I’ll never jump out.

Brack: Are you quite sure?

Hedda: Yes. Because there’s always someone there who’ll … Brack [laughing]: … who’ll look at your legs, you mean?

Hedda: Exactly.

Brack: Oh well, good Lord… .

Hedda [with a gesture of dismissal]: Don’t like it. … Then I’d sooner stay where I am … in the compartment. Two people alone together. Brack: Well then, if somebody else climbs into the compartment.

Hedda: Ah yes … that’s quite another thing!

Brack: A trusted and sympathetic friend …

Hedda: … who can converse on all manner of lively topics …

Brack: … and who’s not in the least academic! Hedda [with an audible sigh]: Yes, that really is a relief. Brack [hears the front door opening and listens]: The triangle is completed. Hedda [half aloud]: And the train drives on.

How does Ibsen make this conversation between Hedda and Brack so memorable?