The fear that stops people from FIRE is, in retrospect, totally irrational. You are valuable. You are worthy. You didn't trick anyone into your current employment situation. There will be some way for you to earn money in the future. It won't feel like failing, and no matter what, you got to have a nice break of (probably) not inconsiderable length.
So I did the FIRE thing for over a year, and re-entered the workforce about ten months ago. Right now I'm super happy I did, not because I'd be hurting for myself, but I wouldn't be able to help out like I am now. And that would make me feel like I wasn't meeting my responsibilities.
I can understand, from an academic perspective, that I don't actually have responsibility beyond my immediate self/family, but it's pretty great to be able to help.
That said, it is 100% by choice, the working. It's a great job with crazy good situation as far as work from home, benefits, and compensation. And I never would have found the job while I was still working, and I certainly wouldn't have gotten paid as much. Because I knew the money was more of a marker than anything I really needed, I perversely felt more comfortable asking for a lot, fully expecting them to balk, half hoping I could just stay in my hammock.
So for me, that would have been what I missed out on. I'd not be able to send grocery money to my tenants who can't afford rent right now. I'd have to be cutting my own spending a bit because of tenants not paying rent, but I probably could have handled that. I would have food from my garden I could deliver in lieu of cash, but after a year of doing it I was sort of over growing food. It wasn't unsatisfying, but once I'd figured it out...you know...more chores.
But when I was ready to FIRE I was ready to fuckin' just go for it. I needed the time off, and I'm way more awesome now after getting that time off.
So the second risk is that, depending on your skillset, you might not be able to re-enter the job that easily, or you might have to do something else. It's possible we're seeing the start of a sea change in certain professions. Teachers might see virtual classrooms with 300 kids, and 9/10 teachers laid off. Office admin types might find that smaller offices with hotelling space for occasional in-house physical presence type stuff doesn't require as many office admins. I'm already seeing certain middle manager types flailing around trying to justify their existence with work-from-home employees getting shit done with literally zero input from the "boss." This is a minor risk, see opening statements.
The lessons from the last recession tell us that certain fields like architecture never recovered. The people who lost their jobs overwhelmingly had to change careers, and those that did not move on have successfully driven wages down for the entire industry ever since.
But if you hit your number already, your money is now working like a whole separate you, so it's gangbusters from here on out. Great place to be jumping from, either way you go.