* Don't intrude when she is arguing with her characters, and you certainly should never choose a side.
* Don't ask her why she continues to write a book when it only depresses her. She doesn't know that answer either.
* If she bursts into tears in the middle of a restaurant without any previous signs of sadness, just leave her be. She will dry it up soon and laugh at herself. On a side note: Perhaps it's best to shield that laughter from other restaurant-goers as they'll consider her insane.
* Don't ask her how her writing is going unless you have plenty of time (and patience) to listen. Seriously, give yourself at least an hour.
* Never, ever say: "Maybe you're drinking too much coffee." And never come in between her and her coffee (or tea).
* You don't have to offer to read her chapters. But if you say you're going to read them, do it.
* Good comment: I really like this, Lisa. Better comment: Your character is aggravating, and I don't like the flashbacks.
As time goes on, I'm sure this short list that I've compiled will double. Check back to see how to stay on your writer friend's good side.