Why and how are you an adult NEET (not in education employment or training)

If physical or mental health issues bar you I'd consider that different. I never really understood how you can live your life being a NEET. Its a term I've known about for awhile but only recently remembered was a thing. Do you have bills? Do you have autonomy in general? Whats the living situation look like? Is the term offensive? I have a ton of questions really. Not here to shit on anyone I'm just full of curiosity on this one.