Do you really need friends?

Okay, so...here's the deal: I'm pretty normal, I guess. In high school I was by no means popular, but I had a few good friends and that was alright with me. We graduated last spring and so now we're all doing our own thing (college, working, traveling, etc). We keep in touch via a group message and sometimes snapchat. But I've noticed more and more that all my supposedly good friends are beginning to annoy me. I'm not sure, but they kind of strike me as immature, making stupid decisions, but can I blame them? We're still teenagers. Making stupid decisions is normal, and I get that. But while all my friends are away at college, partying with all their new friends, I'm at home living with my parents and working 2 jobs. I went to college for a little bit & decided I didn't like it. I don't regret dropping out, but now I only really stay in touch with 1 or 2 people, but that's because I can't stand the rest of my friends. Maybe that makes me a bad friend, but I can't help it. I guess what I'm trying to get at here is that my entire life I've been a major introvert. People always told me it's unhealthy not to be social, and I understand where they're coming from, but I honestly could go for weeks and weeks and not need any social interaction- I've done it before and got annoyed when people urged me to "get out of the house". I'm perfectly fine being alone. I don't need friends and they don't need me. Is that really so bad? I exercise, I eat healthily, and I shower regularly lol. I go to work and get paid so why is that lifestyle seen as unhealthy when I'm perfectly content? I have plans for a bigger and better future, but I just need to save up a little money first. I just want your opinion on this whole no friends thing. Thanks :)