Oh, you're absolutely right. And that is what I try to do now, not care and it's working.
But you know, in some cases it's more difficult not to care, because it's the people I either have to live with or want to live with. Then it does become difficult, then there is only one option. Very less communication with them since it's useless anyway, you can't talk about nice things with them, they only have weird things in mind, you can't tell them the truth, they don't believe it anyway. So there is actually no communication or very less communication possible.
I've decided to from now on communicate less with them and continue enjoying myself.