I have to admit the only wine that I ever thought was special was Petrus.

I'm also fairly sure that if they weren't labelled differently, I wouldn't be able to tell much difference between two red grapes or two whites. I'm a bit cynical about other's ability to do so as well, but politeness prevents me from expressing it. Sometimes it's good to have something to talk about, so you let the group's wine connoisseur go on about the provenance of whatever you're drinking.