Yes, the classical guitar is really really tough to play, as compared to playing the piano.

For piano, getting the right notes is relatively easy. Just know where to press, and control your fingers, if you get what I mean. For the classical guitar, you have to find the right notes, then your left hand has to press properly, then you've got to control your right hand plucking..

Haha. I had, and still have, a relatively horrible time trying to work on new pieces. On the classical guitar, of course. Kinda made me regret quitting piano so early, it's so much easier compared to guitar! (Then again, could be because I'm so comfortable with the piano already, but quite new to classical guitar.)