The waiter hovers nearby after pouring a taste of the wine you ordered, waiting for your response. Should you smell the cork that has been placed on the table? What if it's a synthetic? Should you smell that, too? What about a screw cap? The wine isn't what you thought it would be. You don't even like it. Should you accept it anyway? Or send it back for another selection?
An old world mystique has developed around the ceremony of wine service in restaurants. What gave rise to this quaint formality in the first place was the high incidence of cork taint. Before the rise of alternative closures, an estimated 5% of all bottled wine exhibited its ill effects: wet paper aroma, loss of aroma and flavor and odd, chemical aspects in both aroma and flavor.
Since one bottle in twenty held in a resturant's cellar would suffer from cork taint, it was necessary to present each wine to the customer for his own evaluation. Corks were to be sniffed for the telltale signs and a small pour was to be sniffed to insure that the wine was sound.
"Sound" is the operative word here. Unsound, that is, cork tainted or otherwise damaged wines should always be returned. But these days the incidence of damaged wine is very much reduced. In my personal experience I only remember two examples of tainted wine served to me in a restaurant—this out of hundreds of bottles. Nevertheless, the ritual continues.
If the wine you ordered is not physically damaged, you should accept it whether you like it or not. If you're not sure, ask the restaurant's wine steward to check it out for you.