A new construction has slipped into my venacular and it's driving Adam insane.

"Yeah/no." Say something, anything that requires a response and I'll preface my comments with "yeah/no."

Adam: If enemy forces wanted to torture me, all they'd have to do is fit me for contacts. I hate contacts. I hate anything taking up the real estate of my eyeball.
Sarah: Yeah/no. Why do you think I'm always running to dig eyelashes out the second they fall in?
Adam: ...

Adam: It's like flag-to-flag races just aren't exciting anymore.
Sarah: Yeah/no. Like back when we were mad for Ferrari in 2002, it was cool, but now...
Adam: Yeah? No? Make up your mind, woman!

Adam: Could you set up the coffee?
Sarah: Yeah, no. I'm on it capt'n.
Adam: AAAAAAAAAAAAAAAUGH!

He claims the yeah/no phenomenon has encroached on my vocabulary in the last month or so, and he hates it. Of course, he likes to make me insane with his recent co-opting of the very annoying pronunciation of "across" with a bonus t. He's not from Jersey and I'm not indecisive, so what's going on?

In the case of the yeah/no, I believe it evolved with help from my laziness. Work with me here. In the beginning, there was "Yeah, you know" (or "yeah, I know") which turned into "Y'know," (a phrase my agent hates) which turned into the "yeah/no" we know today, an economical statement allowing the listener freedom of interpretation or a ticket to wife-icide.

I am trying to excise it, so feel free to bust me on it.