I have two, these also fall under the worst bit of racism I have ever experienced as well.
First, this is like circa 1989, I was six. To lay some back story, I'm the daughter of a bi-racial couple, my mother a black woman, my father white. I resulted in being white in skin color. So back to 1989, I was walking down the street with my mom and my grandma (my paternal grandmother=white) we happen to pass by a friend of my grandma's on the street whom she had not seen for almost a decade, the woman looked at me and then my grandmother, totally bypassing my mother and said "Why, Evelyn, I didn't know you had another child, how amazing!!!" I suppose it would be amazing because my grandmother was 67 that year.
Can you spot the ignorance?
Second and maybe more devastating, why only afew years (1993) after that scene my little brother attended the same school as we were only 2 grades apart (a little more back story out of my four sibling and myself my brother Lloyd was the only one who got a fraction of my mother skin color, he being a beautiful light tan brown), I introduced my brother to my teacher.
"Mrs. Gray, this is my little brother Lloydie."
Her eye popped outta her face, and she asked
"Which one of you are adopted?" her eyes lingering on my brother.
My brother cried for three days after that incident.