The value of the question: Questions should be original and on topic. They aren’t required to be, but AMAs are a unique opportunity and it is sad to squander them by asking 100 iterations of “if you could fight 1 horse sized duck or 100 duck sized horses.” Please try to encourage thought-provoking, discussion-inspiring questions that OP would not likely be asked anywhere else.
Civility and Politeness: users are free to (and encouraged to) ask tough questions. But this should be done in a respectful and polite way. There’s no need to use harsh language, and a comment that treats the OP like a person is much more likely to be answered.
Asking for Proof: having legitimate posts is vital to maintain the integrity of /r/iama, and makes it much easier for everyone to see the legitimacy of the post.
You should downvote insults and rude behavior. This is not to say that you shouldn’t ask tough questions. But do it in a civil, polite matter, no matter how much you disagree with them. The OP took the time to come and share their thoughts, and they shouldn’t be harassed for doing so.
You should downvote and report non-questions and other “substanceless” comments that don’t make an interesting point or ask a good question (Ex: “I love you!”, “No questions, just wanted to say hi”). This also applies to child comments and reply to the OP. Followup questions, remarks on their answers, etc. are all encouraged, but jokes and puns should not be.
You should downvote and report joke questions that aren’t intended to get a real answer, especially in threads where the OP probably won’t be able to respond to everyone. For example, “Do you even lift?” in every single AMA about athletics.
You should downvote attempts to back the OP into a corner; asking tough questions is fine, but don’t specifically try to put them into an uncomfortable or awkward position. This is a place to get information and learn about someone else’s opinions, not score points or further your own agenda.