It does not have to be that bad! It depends upon exactly what has happened. Even just a general overtone (or taste) of mustiness quite likely indicates it is 'corked'. I would return it if it were thus. Sometimes it is so slight you don't realise it till you've drunk a glass.
It's so called because the most likely cause is that the cork has reacted with the wine. Spoilage can also be caused by the cork shrinking, and so letting air in (hence bottles are stored so the cork stays damp), or contamination at the time of bottling.
I know purists would differ, but I say 'roll on plastic corks'.
Catso, it would seem that plastic corks would solve the problem and I recall Paul Rankin (tv chef) saying that a plastic 'cork' did not detract from the wine.
The only real problem I have with plastic corks is that a lot of corkscrews don't seem to like them, and they can be particularly difficult to remove from the corkscrew once withdrawn from the bottle. If you must have a cork then I guess they're a decent bet, but a lot of quite good wines these days are coming in screw-cap bottles. The one exception I would make, and where I would always want a traditional cork, is champagne.
Agreed Narolines, champagne has to be the exception. I noticed that a lot of wines were coming with screw tops too, which I found weird as I used to think that only cheaper ones had screw tops - concorde etc yuck.