I've only done something like that once, and it was over an $11 Bordeaux I had at a restaurant in Denver: the Chateau Saint Sulpice 2003 Bordeaux.
Image from www.cellartracker.com.
The 2005 label was the only one I could find.
When I returned to the East Coast, I started asking every wine store in town if they carried this wine. They all said no. At this point I was determined to find it, so I started looking online at the inventories of large wine stores in New York City. I found two that carried it, and the next time we went into the city, Econo Boy and I bought two bottles.
A week later, we opened one ... and it was awful. Sharp, too alcoholic, no hint of fruit or the lovely soft finish I'd enjoyed at the restaurant. Baffled, we corked the bottle halfway through. What went wrong?
The next night, I poured myself a glass from the half-drunk bottle (I wasn't about to pour it out, not after all the work I'd done to find it), and was stunned to find that it was now delicious. A bit of Internet searching revealed my mistake: Bordeaux needs to breathe for at least an hour, preferably two. Oops. (I should note that anyone who knows anything about wine is probably laughing at me and my total ignorance right now. Oh well. The best way to learn is by screwing up, right?)
Does popping the cork two hours early sound like a drag? Buy a decanter.
I always thought these were just pretentious, goofy pieces of glassware, but now I understand what they're for!