"Don't grow old, Pyotr, nothing but pain and disappointment wait for you there."
"I will try, grandfather! Truly I will."
"I promise, grandfather!"
"Good!" said grandfather with a cackle that quickly collapsed into a fit of dry, hacking coughs.
Seven hundred and forty-six years later "Peter," as he was now known, thought back on his promise and cursed his grandfather roundly. Turns out it's not growing old that leads to pain and disappointment, it's existing.
Though, to be honest, that may have been seven hundred and forty-six years trapped in the body of a six-year-old boy talking.