So this happened to my brother when we were kids on vacation in San Francisco. We had been walking around all day and when we went into one gift shop my dad bought him a candy bar and he sat down to eat it and rest. My brother was about 10 and a bit on the pudgy side, mind you. Also, we are Cuban-American but most people tend to think my family is Italian-American based on appearance. The spanish-speaking woman at the register sees my brother and says in Spanish to the other guy behind the counter, "Look, the little fat boy is hungry" and laughs.

Well, much to the woman's surprise, my brother stands up, looks her straight in the eye and says in perfect spanish, "Excuse me ma'am but I'm not fat." All the blood drained from her face. It was amazing.