A stubborn Donkey

Every now and then my brain is behaving like a stubborn donkey.
When it has got an information saved on the `hard disc´ it seems like it can't change it.
Many times in the nights I stand like a fool in front of our guests when we ask where they are from. I tell them you are from England and they say they are from Norway or something.
It's maybe expected that I should know where some of the guests are from. Specially when they have been visited us 10-20 times. But the problem is when my brain has wrongly registered somebody in a country it can't get it right anymore, which means I place the people in wrong country night after night until they maybe get really mad at me.
I wonder if this disease has got a name? I don't know.
Maybe I am just senile.
As an example I have a lady that has visited us, together with her husband, at least about 20 times these two last years.
When I get to their table I can't ask them where they are from when I feel I should know it now.
And my brain has registered they are from Sweden somehow, but every time I say it they look surprised and tell me they are from England. I can't understand why I can't remember it. I feel so stupid! And every time I say Sweden I really think `I'm right tonight´.
An other example is a couple that is from Holland or Germany (I still haven't learned where they are from) and I say every night they are from Denmark even when they have corrected me aboute 5 times so far. Now I know they are not from Denmark, but what would I say next night they show up? I think they are from Holland or Germany but I am not sure.
Clas always want me to go out and ask where everybody´s from, but now I would like to pass it on to him. I have put myself on shame so much now that it's enough! *sigh*
Maybe you think we shouldn't ask at all where the guests are from? Yes, we could just forget about it. But many times we see new friendships established among our guests. Specially when they come from the same country. We don't like to deprive the opportunity for our guests to make new friendships and it's quite interesting too, to know where the guests are from.