tsutton makes good points. Especially when you're having wine that has been shipped a long way or stored in hot conditions there are many many bad bottles. Luckily technologies have improved and there's much less spoiled wine around that there used to be. So, the tasting process is a huge affectation, absolutely, and a wonderful opportunity to be pretentious too, but it does actually have serious benefit.

For those who think it's all hype: I recently served two wines to a small group of very pretentious guests who consider themselves experts on all things wine. A bottle of Chateau Lynch Bages '98 was one and a bottle of Bettu Meritage '02 (maybe the best Brazilan producer) the other. I decanted both, cleaned both bottles well and exchanged the contents with each other. Obviously the Lynch Bages won. A second set were tried, not switching this time and the Lynch Bages again won. My two experts hadn't a clue. Of course they both were excellent wines both, and had some strong similarities in style, but not even the same grapes.

I'll be in trouple if any of them happen to read this thread and recognize me!