So confession: I have a banter addiction.
I love writing byplay, snarky asides and snappy patter amongst characters. If ever two characters who are clever, witty, sarcastic or just plain talkative get together, they are bound to riff off each other. Sometimes, it only takes one character and anyone they know they can get a rise out of. I have to be careful that these exchanges don't go on so long they derail the motion of the story entirely - and, of course, since minimal description is helpful to keep the pacing, it runs the risk of becoming talking heads.
Then there are narrators like Vil (or Trin in the zombie novella I'm working on) who have a bit of an askew world view, and that shows through in the way events are described from their perspective. If this is not quite banter, then it is a close cousin.
In Who Wants To Be A Hero? I let the banter run wild: it was a humorous novel, after all, and the strong structure kept the story moving. With Unnatural Causes, I often decided to cut it off, particularly when Vil and quasi-ally, quasi-antagonist Duvalis got into it ... but given the final length of the manuscript, I may go back to some of those conversations and let them take a natural course for a few more exchanges. Of course, Flow has quite a bit of patter between Kit and Hadrian, the first (and probably my favorite) exchange being where they riff about Hannibal Lecter.
(Of course, one only knows that Lecter has a rare form of polydactyly (like Hadrian, hence the initial salvo) unless one has read Hannibal, the book on which the movie is based, which begs a question about Kit's fifteen year old reading habits ...
It might be mentioned in the novel version of Silence of the Lambs, too? Not sure, been too long since I read it.
Maybe the reason I like banter so much is I myself am hopelessly addicted to theatric asides ...
(Is this the right way to punctuate multiple parenthetical paragraphs?)