Confront them about it and offer to pay them $5 to read a book teaching you to be nice to people.
I can't even make up the stuff my dad comes up with sometimes. (see the Memory Monday post: where my father tells me that the fate of a young girl who runs away is to be kidnapped and turned into a crack whore...) Ahem...
When I was a kid/teenager/young person, I had a dual personality. In public, especially at school, I was about as perfect as a kid can be. I desperately wanted my teachers to think I was a perfect pupil/person and for the most part, they did. I was always teacher's pet without ever being that annoying kid that everyone hated... But my perfection didn't carry over at home and I was... not always super nice to my parents or my siblings.
Once, when I was about 14, in an effort to teach me some people skills that weren't based on my need to have my teachers like me, my dad came to my room, told me I was sometimes a bit of a brat and told me that he would pay me $5 to read a book by Dale Carnegie called, How to Win Friends and Influence People. I don't know that being called a brat (or some other, more 'father friendly' term) really swayed me, but being offered $5 just to read a book sure did.
So I read the book and was amazed at how simple some of the things Carnegie taught were. Things like noticing the names of the grocery checkers, or asking someone you want to do business with what interests them instead of talking about what you like. Or one of my favorite stories — The man who couldn't get the rowdy kids who hung out on the corner by his house to be quite. So he paid them to stand there for a few hours. And each night, he offered less and less money until they finally decided it wasn't worth it and went home.
I won't lie and tell you that this book immediately changed my life and made me this super awesome perfect person. (As is clear by the fact that my dad came back about a year later and told me he'd give me another $5 for reading the book, but this time I had to take notes on it) But I will tell you that it changed something. If nothing else, it has made me increasingly aware over the years (because I've reread it a time or two without the additional motivation of my dad's five dollars) and there is a lot to learn from Carnegie's rather simple observations on life.
In defense of my dad — He remembers offering me the money to read the book, but he denies ever having called me a brat. Maybe he didn't say brat specifically, but I do most certainly remember the feeling of outrage at whatever he did call/tell me when explaining why I needed to read this book.