Writers aren't exceptionally mean, even to other writers, but it does somehow seem that way, because of the way we leave our egos exposed. No wonder others are tempted to at least give them a good swift kick now and again.
"How's the novel going?" (unless you know the writer is a demon of productivity, in which case there are other ways of getting their goat) is one of the great questions. It seems to come out of genuine interest, maybe really does come out of genuine interest, but a certain passive aggressiveness that leads, when deployed appropriately, to dismay, depression, and defensiveness. Well played!
Yeah, I asked a couple of people that at Readercon. You may ask why, if we treat each other so badly do we hang out with each other? First, it's because many of us are genuinely entertaining, at least to each other. Second, by the same token, no one else finds us as entertaining as we do.
And I did have a great time last weekend, and had to take a long nap the day after to recover.