Do you ever notice when you try to be sarcastic with people who are equally if not more sarcastic they take you too literally sometimes?
Granted, with some people it's very hard to know whether you're being sarcastic, but I think it brings up an important point that we should never assume the worst of people especially when dealing with a sarcastic conversation.
Or maybe we're so sure of ourselves we forget that other people out there have their own flows or "styles"...