I find the FIRE movement fascinating but also slightly depressing.
Among the actually old (my parents' generation - in their 60s and 70s) retirees I know, around half of those retiring from decent 'knowledge worker' jobs have kept on working part-time to some extent. They are consultants, advisers, board members, independent researchers, and so on. They seem to be very happy - they are working at something they are good and believe in, while not having any economic constraint forcing them to work more than they want to, or for anyone they don't get along with.
I can't imagine having 'Financial Independence', but not wanting to do something like this. I enjoy my work in general, and I would enjoy it much more if I had almost complete freedom to plan my day and to walk away from toxic situations. But all the FIRE people that I see online seem to be basing their lives on the other type of retiree - the ones who take leisure activities and sports such as bowling and tennis far too seriously, read and watch constantly but quite aimlessly, and go on endless trips to 'tick off' different world destinations.