There's an old saying, "Never try to teach a pig to sing; it will only waste your time and annoy the pig."
That said, do you ever find yourself arguing with people you loathe? Not necessarily someone you have to talk to, but someone you just can't help trying to re-educate?
I need to learn to walk away. There's another old saying, "Hitting yourself in the head with a hammer feels so good when you stop." Okay, maybe that's just something my dad made up and it really isn't a saying.