At one point the discussion turned to writing dialogue. I can't remember who said it now, I think it was Russell T. Davies, but one of the writers described real life conversation as being like two monologues.
This comment reminded me of a snippet of a conversation that I recorded one night as I went home on the bus:
Woman: You kicked your teenager out of your home? How old is she?
Man: No, she went to move in with her boyfriend
W: My baby's going to be 16 next week
M: I never liked the guy
W: I can't believe she's going to actually be 16
M: He's one of these wannabe homie types
W: I'm sure she'd like to move out if she could afford to support herself
M: There's nothing worse than a wigger
W: She's so independent
They were so intent on telling their own story that they didn't even hear what the other person was saying, and there's something really fascinating about this, far more so than if the woman had shown polite interest in what the man was saying to her, or if the man had accepted the change in conversation and shown interest in the daughter's upcoming birthday.
I wrote it down at the time to remind myself that people don't always answer each other's questions when speaking to each other. In fact, sometimes they aren't listening to each other at all.
Going back to the Screenwipe special, the discussion of dialogue was only one point in a very interesting programme, I highly recommend tracking it down if you haven't already seen it.