Pretty (and) Stupid

"You can't be pretty and smart."

Yes, my mother in law really said that. A few times she would say to my cat, "It's a good thing you're pretty, 'cause you sure aren't smart." She likes to say things like this when I'm around. She must think that I don't know the game she's playing. Just because I choose to stay quiet doesn't mean I don't know anything. One of these days I might actually challenge her little theories. But that's exactly what she wants, to strike a debate with someone so she can use her vast intelligence to prove them wrong and show that she is all knowing. She tried that with my mom the first time they met, but what she wasn't counting on was my mom being very educated about Native Americans as well. She dropped that after the first question haha.
But anyways, I have so many questions about this that I would love to hear her answers for. After all, it's just a cat, what do you expect? A college degree? And since looks are all about opinion, how does that work? Some people think I'm pretty and some don't, so which is it? Am I stupid or smart?
Cynthia, you must be pretty fucking hot because that is one of the dumbest things I have ever heard.