Is high school ever really over?

The other day, I was watching the Jane Austen Book Club (an excellent movie that I would highly suggest if you have not seen it) and in one scene, a woman gets in a fight with her husband and she says to him “High school is never over.” reading another question tonight reminded me of this and I would like to hear ideas from everyone, even those who haven’t yet graduated from high school and those who never graduated from or even went to high school.