NOT TODAY - almost

I had to get to the chiropractor early this morning.  I'd just been there yesterday, but my back was killing me, without doing a complete job.

This doctor has two young ladies who do the front office work for him, and this morning one of them said, "You owe us two jokes."  Oh, dear!  Well, I dredged up this one:

What does it mean when people say, "That's a great question"?
            It means they don't know the answer.

            And what does it mean when they say, "That's a dumb question"?
            It means they're not going to answer it.