Just treat people as NPCs since you're the only player character in this game. That's what I do anyways.
You want to know the secret? It’s simple really all you do is- oh wait a rhetorical question huh~ never mind then ☕️\(•~•)
Simple, continue doing what you are doing and don't reply to any comment here, don't like and don't read any thing on this thread, if fact just be like this
Do a double take, see that they’re literal mushroom that sprout everywhere regardless of your will, then move on because you’d rather have some French Fries
Why do you need to not care about people? It's fine to care. Not like you have to do anything about it. What's up? You feelin' bad because you were too lazy to wash the dishes and your mom had to? No worries, man. I mean, sure, you're an irredeemable asshole and all, but what matters is that feeling bad about it doesn't mean you have to change or anything.
Grow a pair. Indirectly asking people on the Internet for moral support(or whatever this is) on the Internet is not the way. @Edit Or if some Dr. Phil would say, if you're concerned about people's opinion, you're truly concerned about your own opinion about yourself, therefore you should upgrade yourself. Then again, alcohol is also a solution.
I dont Ccar too much about myself, much less other people. Depression, supreme self confidence or apathy/Obsession can Help you (but Not without a Price)
Read stories or watch movies about how shitty humans can be over and over again until u lost faith and hope on humanity itself.......
Read Warlock of Magus World or Reverend Insanity and let the chunnibyou power overcome your rationality