As a teenager, I was quite self-conscious of my looks, especially my skin color. I grew up in a town that had more whites than blacks. Except for hearing Asian Indians, there was not much diversity that time. Even some of those Indians were lighter-skinned than me including my father and sister.
I rebelled to the point that I actually refused to go out in the summertimes, not even go swimming. I instead mostly stayed home all day, watching TV and reading books, to my parents' dismay. From time to time, I would attend art class or visit a friend. But that was basically it.
Finally, after two years of this self-deprecating behavior, my Indian friend advised me, "Don't 'punish' yourself. You're still nice looking."
Then one day, my grandmother told me this story.
When I was quite young, at least two or three times a year, my mother and I (and my sister, after she was born) would go visit my maternal grandparents while my father stayed to work.
My grandmother often helped taking care of me, mostly enjoying her grandparent role, and giving my mother a brief break.
One day, my grandmother was giving me a bath. I was about 3-1/2 years old that time. She scrubbed me vigorously from head to toe.
As she was toweling me dry, I glanced at my arm.
Pointing at my arm to my grandmother, I complained, "Wash more! This dirty!", referring to my medium brown skin. She tried explaining to me that it was permanent.
I thought it was interesting that me, only 3-1/2 and D-E-A-F, understood to some degree that people have different skin colors!