How not to talk to writers at SF conventions

I see my fellow writers making "How to deal with me at Gen Con" posts. In keeping with the fundamental negativity of my attitude, let me list a few things you should avoid saying to a writer if you want him or her to regard you as congenial company.
1. "I never heard of you (or read your books.)" (99% of the time, it's perfectly understandable if you haven't. Few of us are superstars, and we don't assume you're familiar with us and our work until you let us know you have. You don't have to rub our noses in our relative obscurity.
2. "Here's what I didn't like about such and such a book..." It's already published. I can't change it now. You're certainly entitled to hold and express your opinion, but if you want the writer to enjoy the conversation too, maybe focus on something a little more positive?
3. "Here's how your book violates the established continuity of the shared world..." The comments on 2. apply here as well.
4. "I read your books, but I don't buy them. I download them from a pirate site." If you do this, you're cheating writers out of their royalties. Which you shouldn't. But if you can't resist doing it, telling us is like stealing from us and then taunting us because you got away with it. It's adding insult to injury.