I suppose
Lalwende has said it all. Generally I find parody boring & unconvincing, but most of all its cheap. I distinguish it from satire, I suppose, which I usually understand to be more subtle.
Its Tolkien parodies that don't interest me specifically, as they are almost never well done. Of course, there are always exceptions!
At Oxonmoot two years ago we were presented with The Reduced Silmarillion, which was hilarious, because it was written & performed by people who knew the book. Its difficult to give a true flavour of the thing, but all the parts were played by men (Luthien Tinuvial being played by a guy in a blonde wig was something to see), Ulmo was a three foot high inflatable penguin, & in the Last Battle Morgoth's dragons were paper aeroplanes. Farce, yes, but deeply moving in its own way
(& to be repeated at Tolkien 2005.) Though, to be honest, what I especially liked about that was that it depended on the audience having a real knowledge of the book.
I suppose my position is that I'm not against parodies as such, they're just not my thing.