Brother: I cant believe people pay £80 to go to the theatre, once you've seen one musical you've seen them all.
Mum: Well its the experience isn't it.
B: I suppose. What about that Othello? Have you seen that?
M: I've read it, I've never seen it.
B: That's like one of the main plays ever innit?
M: Yeah.
B: Yeah, what are the other one's? Its like Othello, erm... Tempest...
M: The Tempest, yep.
B: What else?
[silence]
B: What about Chocolat?
[silence]
M: I've read the book, never seen the play. The book's called something different, but I can't remember what.
B: Is it Chocolate?
M: I can't remember.
B: Is it about a brothel?
M: No.
B: What's that Indian sex book called?
M: Dunno
B: Is'nt it the Karma Sutra or somethin?
[silence]
B: Is that a play too?
M: Probably yeah.

Why did this conversation make me so angry?