I hae a friend like that who, even if she comes to my house, will insist on drinking the wine she brought with her without even looking at what I'm serving first.
This is because ONCE, about seven years ago, I send my (now Ex)husband shopping wtih strict instructions to get a nice bottle of white and definitely not Chardonnay, as I know my friend is picky about wine and that she hates Chardonnay.
Being the dick he is, he came back with two bottles of £3.99 Chardonnay and it was too late to go to the shops for more.
All the same, I do find it rude that she won't drink anything I bring. Last time I went to see her, she served her own wine and beer and then insisted on giving me back the wine I'd brought - I felt like saying, what am I going to do with it, I'm bleeding pregnant!
I don't know, I was brought up to eat or drink whatever was put in front of me at someone else's house, even if it's vile. The number of times I've forced smoked salmon (which I loathe) down while going 'Mmm, yummy, what a treat!'...
So next time, I'm going to wait until she's poured her own bottle, then whip out something really delicious and expensive for the rest of us to enjoy. Any white wine recommendations (not that expensive though - I am poor!)