Gerald tries to provoke a response from Sheila in the way he goes on at her, "I have been trying long enough, haven't I? (As she does not reply, with more instance) Haven't I? You know I have." Even then, Mrs. Birling has to reply before Sheila eventually comes back with what is described as a "half serious, half playful" comment that she agrees with Gerald but points out a time the previous summer when they never came near each other. This is an unusual thing to say when celebrating your engagement and even when Gerald defends himself Sheila simply replies with a sarcastic, "That's what you say"; and it is left to Mrs. Birling to end this exchange with a light hearted remark of, "Now, Sheila, don't tease him". The audience will probably pick up on this and it creates a sense of tension, this is obviously a subject which Gerald and Sheila feel badly about and the audience becomes interested in what it means, it stands out as the happy situation of the engagement party has been tarnished slightly. In fact we later learn that Gerald was involved with Eva Smith in that summer and let her stay in a friend's house.
Mr. Birling's position in the family is also made quite clear on a couple of occasions. He is the man of the house although unusually his wife is of a higher social class, this means he almost has something to prove and must work a little harder at gaining respect from his peers than other men at that time. Mr Birling is immediately recognises the possible business advantages that the marriage may have, he makes it clear to Gerald that he hoped one day, "Crofts and Birlings are no longer competing but are working together - for lower costs and higher prices". Mr Birling is also a key finger in Act I for a couple of speeches he makes to the newly engaged and everyone else present. Firstly he talks about the future and what it holds, not only for the family but the world in general, Priestley uses "dramatic irony" to bring another amount of unease to the situation.