I'm "semi-retired" now. Which is not retired, really, as I still have to think about work.
My father-in-law is "semi-retired," which to me looks mostly like his pre-retirement. He started some kind of logistics company for trucking/shipping years ago and worried they wouldn't "let" him retire, by which he meant they would rely too much on him and he wouldn't be able to bring himself to pull the trigger on them. So he moved from Denver to Colorado Springs and commuted the last few years he worked full-time, thinking that adding distance would subliminally get in their heads and they'd start to consider him as an old man who's not gonna want to make that drive much longer. Then he retired, and the people in charge at that point offered to let him work remotely on a flexible schedule. (I say "let him"....I think he still owns 1/3 or 1/2 of the company, and I don't know how they'd stop him, exactly.) Now he works from home M-Th, which, I mean, doesn't seem like retirement.
But it's his choice and I know it's because he enjoys it. And because he was obsessed to an unhealthy degree with golf, which he gave up, and now I don't think he has enough other interests to keep him going. Unfortunately he has virtually no relationship with 2 of his 3 kids, and his relationship with my wife and her kids isn't ideal, mostly due to the fact that he's married to a crazy woman.
Financially, he did great. He works purely because he wants to, and as far as I can tell he's set for life several times over. He lives in a gorgeous, massive home on some beautiful acreage, a setup I could only dream of affording even with both of us working, and every couple of years he randomly gifts his children a chunk of money, just because I suppose he has it and because he can. Personally, his situation is a runaway dumpster fire, to the point that we have to receive the money he gives to his son and other daughter and distribute it to them, because he can't contact them directly. That's as much on his end as it is on their end. I shake my head and try not to judge because I don't have kids and who knows if I'd have done any better. I do note they don't mind taking his money, even if they don't talk to him. It's kinda weird, because my sister-in-law is married to a very wealthy man and they can hardly notice the money he occasionally doles out. For me and my wife, it's like holy-cow-this-is-quite-a-gift money. For my brother-in-law, it's basically life-changing money every time it happens.
I'd be more than lucky to wind up where he is, $-wise. Otherwise, he's almost like a What Not To Do warning avatar.