My (still living) grandparents are about to become great-great grandparents. I've never known a living person to get to hold their own great great grandchild before
As the youngest child of two youngest-child parents, I never knew my great grandparents, and only had my grandparents for about 20 years. Had I known I'd only know them for such a short time, I'd have spent more time with them. Regrets suck.