I finally saw Sideways Friday evening. I thoroughly enjoyed it, but fear that the hullabaloo over the wine scenes and pinot noir good--merlot bad obscures a pleasantly depressing story about middle age and failed dreams. In that sense it reminded me a bit of Freak Talks About Sex, an unfortunately titled movie that focuses on guys in a similar situation around the age of thirty, though there was no wine or other obvious hook on which the story hung.
I would hope that people don't take the main character's behavior as a template for attending tastings. If you don't like a wine, there's no reason to insult it in front of the person serving. (Obviously I've said bad things about wines here, but that's to help avoid those in the future.) At a tasting, the person doing the pouring either works for the winery, works for the distributor, or works for the shop that's selling the wine, and is certainly aware of the quality of that wine. Besides, once you get away from obvious flaws, it's all a matter of taste anyway, and opinions are like... well, you know. Anyway, there's no reason to be rude to the person who is, in many cases, providing you a free sample of a luxury product.
One thing I focused on in the movie was that I felt the true wine lovers were the two main female characters. They adored wine, but didn't take it to obsessive levels, and had the rest of their lives in order. For Giamatti's character, it seemed like he could have fallen into old record collecting, rose growing, or any other activity that would provide him with lots of misery and only occasional flashes of pleasure. (I used to know some fanatical rose growers, and they hated 99% of the roses they saw in public or in print. I've never understood the attraction to a hobby that keeps you miserable most of the time.)
It's a complicated film, and I'm looking forward to watching it again and with the director's commentary.