don't know why anybody would want to work forever, unless they are truly passionate about their work which i would bet 90% of people are not
time is your most valuable asset, no amount of money buys back time but when you work you are trading time for money, i'd rather be a broke 20 year old than a billionaire 70 year old
i think people that say they are bored in retirement and then come back to work are just too embarrassed to admit they need the money, you don't have hobbies to entertain you? you don't have friends and family you would rather spend time with than the annoying and gossiping coworkers or asshole boss? you would really rather greet strangers at wal mart than watch a movie or take a walk in the park? do paperwork over going fishing?
it's different if you're the one in charge making a lot of money, and you're a workaholic that needs to stay busy and you consider everything else to be a waste of time, but most people are just trading time for money and don't want to admit they didn't make wise decisions with their money
E