What is the humour behind these lines in 'The Importance Of Being Earnest'?

Question

In Act II of Oscar Wilde's The Importance of Being Earnest, Algernon and Cecily have this exchange:

Cecily: I can't understand how you are here at all. Uncle Jack won't be back till Monday afternoon.

Algernon: That is a great disappointment. I am obliged to go up by the first train on Monday morning. I have a business appointment that I am anxious . . . to miss?

Cecily: Couldn't you miss it anywhere but in London?

Algernon: No: the appointment is in London.

What is the humorous meaning behind these lines?

Answer 1

Algernon is looking for an excuse to leave before Jack gets back. Rather than saying he has to be present at a business appointment, Algernon says that he has to miss the appointment. The humor is that there is no reason to take a train to another place in order to miss an appointment: he would also be missing the appointment if he stayed with Cecily, and yet he pretends he has to go on a train to London in order to miss the appointment.

Jack describes Ernest as wicked and lazy elsewhere in the play, and so Algernon seems to be trying to play the part. The fact that Cecily accepts the excuse highlights her tendency to take things extremely literally.