Everyone else you know now would die centuries before you.
Your 600 would be not much different to being 120, when all your kids died at 80 something. You'd just live long enough to barely remember the pain of their loss.
1422 was the year King Henry VI was crowned at nine months old. If your 600 years had been from then until now, at which point in the story of our history would you have decided you didn't want to turn the next page?
but we spend a long time dead.