My ex boyfriend won a kids essay contest when he was 10 years old.  He went with his mother to collect the prize.  

There was an older white woman there that told him, "You are a credit to your race, young man."   He wasn't old enough to perceive the slight, and trying to be polite he responded, "Thanks, ma'am, so are you!"   

The woman was taken aback, much to his mother's delight.