The one I remember was annoying because a third person instigated it. Most of the people at the table were adults, plus a couple of teenagers. One of the teenagers was the cousin of the other, and not exactly the smartest lightbulb in the pack. Before the game got started he was talking about his prize possession, which was a piece of Arsenal (London football club) memorabilia. One of the adults was teasing him and asked him if it was a Tottenham (a rival London football team) thing, which he responded "I expletive hate the antisemitic slur". For reference Tottenham fans are often called this name, and indeed use it for themselves.
Unfortunately, we had a Jewish guy at the table, but he missed what was said. So his buddy got the kid to repeat what he had just said, at which point the Jewish guy slapped the kid. Now as I said the kid wasn't exactly smart, and I honestly don't think he know what the word meant, other than the fact it was what you called Tottenham fans. As the GM, I had to castigate both players, telling the kid we don't allow that kind of language, after having to explain why it was offensive, and the grown ass man for slapping a teenager (actually he was lucky, I think if the kid hadn't been so surprised, he could have taken the adult down). I gave the chap who had been teasing the kid a look, though it was clear he didn't expect what was going to be the response. My real annoyance though was reserved for the chap who got the kid to repeat what he had said, knowing how his friend was going to react. It was the first time the kid had turned up at the club, and he didn't come back