This dialogue works particularly well due to Suzanne and Doris’s opposite natures. Doris (the mother) is full of feeling and premonition while Suzanne (the daughter) is cynical. One is over-the-top; one is even-keeled. 

The friction is caused by Suzanne’s need for her mother to come down to earth and by Doris’s need for her daughter to take her flights of fantasy more seriously. 

Mike Nichols, who directed this film, would probably call this a negotiation.