Have the Irish in America had a rough time with race relations in US history? Did anyone call you potato to offend you or make you feel like less of a person? If so, what was the situation?

I think the key to the potential difference in situations is simply history. When an older white teacher tells a young black student to "get away from the door and sit down *****h!", who knows what goes through that student's mind. Reminders of slavery, lynchings, and/or simply being looked down on as being inferior aren't that hard to imagine.

As for people calling others the same thing (blacks calling blacks *****s, Irish calling Irish potatoes, or fat people calling fat people fat), a lot of it has to do with feeling a shared identity.