Great insight that is worth repeating.
One of my biggest problems with FIRE discussions is how much they reinforce the idea that retirement is a prerequisite for achieving happiness. This leads a lot of FIRE-minded people to double down on jobs they hate that consume too much of their time and energy, only because they think it will better enable them to be happy later.
For the lucky few who can be early employees at unicorn startups, that might be true. For the average FIRE person working a $100-200K/year job, they might be better off scaling back to a sustainable 40hr/week job and making a point of taking vacations and doing activities in their off time. Even if that means taking a paycut and delaying their target retirement date.
You don't have to wait until FIRE to start taking vacations, doing hobbies, or working on projects. If a job is consuming so much of your life that you feel you don't have time to do anything else, it's time to reevaluate the job.