The biggest problem with pop culture references though, is that you date your story. The more references, the more likely it is to become obsolete within a shorter time span. It won't appeal as much to future generations if they don't get the reference.
This. This right here. This is why I always make things up. It's also why I try to avoid recent slang.
I think that "We're not in Kansas" is fine because that line has aged well and everyone sort of knows the wizard of oz, it's something that's very broad and can be in age gaps.
Now, talking about what the fox says is something different, this is very current but unless you're publishing that day for a quick thrill on tumblr isn't going to go down very well.
I've just finished my first chapter (YAY XD) of my NaNoWriMo novel and I have used a few pop culture references but I kind of double it up so that it can be read by people who know and not know the references.
"Picking up her brown messenger bag (that she had chosen based on something a character from a TV show owned) and putting on a bow tie over a T-shirt (same character) she pushed out of her dorm room on a mission, she couldn't be late, well not that late."
I do have another ref half a page down that I noticed but I think I'm going to edit that out.