Back in the 70s, as a child, I was popped up a grade, from 4th to 5th, and lasted there about two weeks.

I'd lost all my friends. It was like a death. I'd lost the "team" feeling I'd had with my classmates, and was surrounded by what I took to be cold older guys.

I wasn't an introvert. I was an extrovert. And I missed my compadres.