Are you Asian?
Can Asians tell a block away if someone is Chinese, Korean or Japanese?
I know that in Korea "ugly like a Japanese" is a terrible insult.
I do know Puerto Ricans who get offended if confused with anybody else, including Cubans.
I'm surprised about it because I find Cubans to be one of the most successful immigrations we ever received, very similar to Jews, Iranians, Indians and Greeks.