Learning things, books, music, movies, games, visual art, animes, all the usual NEET things but maybe I liked learning about random stuff I was interested in more as a kid maybe than most people do instead of socializing. I never really felt loneliness like some apparently do. I don't really care about the stigma I guess. I think a lot of people hate it because they wish they could do it and not everyone is able to. I see how some people find it depressing to live like this, but I think it comes down to how you think about it and your particular personality.
A guy I used to know would talk about that cocaine purity test in blow as a metaphor for "getting in where you fit in" or whatever. If you melt at a low temp maybe you should try doing something else, everyones not made for the same things. I melt when I try to fit into the world. One person's paradise is another person's hell. In cases of isolation like this, I think a major part of it is how good you are at keeping your mind stimulated and how you react to other peoples' expectations of you. Worrying about money has been a big problem for me in the past, but I just kind of stopped caring because I tried to fix it many times, and like I said that's where I melt.