My brother worked as a lobbyist until he was 80 and only quit because he was going blind. He was a solo practitioner and loved what he did. For the rare few, who both find work they love and make a good living from it, that is a match made in heaven. I recall all the management books calling for people to "find your passion." For probably 90+% of us that is a prescription for a fruitless search and increased dissatisfaction. Thats one among many reasons why a lot of us optimized our work lives as best we could to achieve FIRE.
Very true. One of my neighbors still runs his own business at 87. He's at the office by 9 every morning and loves what he does. I think it's mainly the idea of having a lot of local companies who use his services, so he gets to hobnob with their execs all the time. But he's also still very active otherwise -- plays tennis 2 or 3 times a week, golf in the summer, and vacations several times a year. The guy is kind of inspirational, even though his lifestyle is utterly different from mine.