It's funny. Most people that know we FIRED at age 50 just accept it. There may be some questions and a little envy, but for the most part it doesn't come up.
My mother, on the other hand, is brutally nasty about our "wealth". She lived with her last husband for 30+ years raking in the money based on his Army Col. pension, plus both of their SS payments. Then he died, the pension went away (no survivorship), and all she has is his (higher) SS payment and a small VA benefit, plus some savings. When I ask her why they didn't set things up so she would be better taken care of, she says they planned for her to die first, because his family was long lived and ours isn't. The fact that he was a smoker seems to have been ignored. I'm so flabbergasted by that (seemingly serious) answer that all I can do is stare at her blankly. All it would have taken is a slight decrease in spending and a life insurance policy. She's not eating cat food, but it's definitely a big change.
So now she's always making nasty comments about how rich we are and how all her friends have flat screen TVs and golf carts to ride around in, and things like that. We tried buying her a few nice things, but it never stops. I have explained to her that we may have a (relatively) lot of money, but we don't get pensions and it has to last us 40-50 years, so we're not living live the Trumps.
None of that matters, and the envy and nastiness keep on coming. It's gotten so bad I no longer expose DW to her venom, and my calls and visits are getting fewer and farther between. It's not the way I would prefer things to be, but it takes both sides to make a change, and she doesn't seem interested.
I think if you get exposed to people who envy your choices so much, there's little to do except limit your exposure to them. Luckily, most friends and acquaintances tend to be more polite than family members.