This is a rant.
15 years ago I was having a discussion with a co-worker, I was complaining that while I liked the day-to-day job back then, I really didn't want to spend another 40 years just “doing work”. So I decided then that I would work hard to earn a lot of money, live frugally, save money, invest, and retire early.
So that time has come, I now basically have a passive income off of investments, I quit my job a few months ago and I'm (relatively) free as a bird (until the economy crashes and my investments are worthless). Just to be clear I'm not super rich: I can afford monthly expenses and have a little bit leftover for fun stuff, but I can't go to crazy expensive parties, buy a lot of crap, and have 10 faraway vacations each year or whatever.
It was fun for the first 2 weeks, I was doing some personal software development projects, playing some games, going outside a lot to enjoy the weather.
But ever since, I've just been depressed. I've been thinking, what am I doing it all for, what's the point? Now I'm not working for another 25 years (and beyond), but what am I doing for the next 30-40 years until I die? I basically have a completely empty life. I achieved my goal of not having to work, but I feel it turns out my goal was wrong.
Work sucked, I'm glad I don't have to deal with corporate bullshit anymore. But some of the co-workers were really nice people, and I miss them a lot. Occasionally I could experience some joy by delivering a cool project. There were some fun and meaningful aspects to work.
My advice is, build something meaningful in your life (potentially in addition to saving for early retirement if possible). Find a nice partner and/or nice friends, find out something nice to do together, have kids (or not). Don't spend all your time and energy only on “not having to work anymore” and then come out the other end completely hollow, unfulfilled, and with half a life gone with nothing real to show for it.
I've seen some threads here and elsewhere on “what would you do when you didn't have to work anymore”, and I mostly see hobbies that people are already doing or “activities”. It could well be that it's fun in the weekends, and that it can be fun for a short extended period of time (e.g. a few weeks). But do you really think that “playing videogames” or “reading books” or “hiking” stays fun for years and years? Try to think about it a bit deeper.
I'm going to try to look if there is any job which is somehow meaningful and adding something positive to the world (instead of just extracting money and resources out of people and the planet like most companies), and maybe see if I can still somehow find love and/or a good friendship at this age.