Being the "dumber" sibling
Growing up, I was the more social, loud kid, whereas my older sister was more reserved. She would never come out of her room to greet guests until she was forced to do so by our parents. My parents would tell her "You should be a little more extroverted Misty." but they never bothered her much about it since she was the "smart" kid, always came first, participated in school debates and clubs, always got top marks, on the other hand, their younger daughter was a loud, average, "ok" child.