I felt the same way as you for about ten of the eleven years that my parents forced me to play piano; that's because, for ten years, I was playing classical music, which I got absolutely no enjoyment out of playing. It was only in the last year that I got to start really focusing on jazz, which I loved to play - subsequently, in a fit of teenage rebelliousness, I gave up the piano altogether and moved onto the bass and the guitar :D. The point is, it's just like the others have been saying - you've got to play music that you like to get anything out of it. If the teacher that you have isn't teaching you what you like, he's probably not the best one for you - see if you can find yourself another one, as hunter said.

Earthman, to cure your bout of guitar aversion - perhaps you could try going to a gig or watching one of your favourite players on video/DVD/internet? I sometimes go through dry patches where I don't feel inspired by anything - then I'll see a player from one of the really good bands at my school playing, and I suddenly can't wait to pick up a guitar.