I was talking to a friend in a coffee shop and we were discussing various features of a Native American language. At some point in time, a woman sitting nearby got rather offended when she mistakenly heard our discussion of a language not having feature x as a suggestion that it wasn’t a real language. She promptly got up and walked out of the cafe before we knew what was happening. I quickly opened the door after she left to shout an apology across the parking lot for any misunderstanding.