It's interesting, as a teacher, to read the various posts here, expressing some degree of frustration with your piano teachers and not understanding where you're headed in lessons.
Sometimes, once students know the notes, the rhythms, the piano keys, the basic terms and symbols, it's easy for them to wonder what else is there for my teacher to teach me? Or as someone above said, they feel like the teacher just basically corrects his mistakes.
Here are some things I think every good teacher should be doing with students who can already read and play at intermediate or above level:
Present technical skills in a planned sequence, helping the student to play without tension, pain, or hand injury, so as to prepare the student for those same technical issues in pieces in the near future.
Help students completely understand key signatures, chords of every key, inversions, cadences, form, harmonic analysis, etc, so that the student can "see" what the composer was working with.
Understand the idea of tension and release within a piece, to create high points within the phrases, to keep a forward motion building to the climax of a piece--helping the student know how to use tempo, dynamics, rubato, etc to achieve these high points.
To understand the various time periods of music, so that the student will know what was typical for that time, in terms of ornamentation, pedal, articulation, etc.
To care about the student's preferences, and find music to accomodate those preferences, while opening his mind to other styles as well.
To know what pieces the student is ready for, to give him useful practice strategies, to have an arsenal of ideas for potential trouble spots, and to ultimately help the student play not only "correctly" but with beauty and emotion.
To help the student to not only read music, but also to play by ear, to improvise, transpose, compose, and other activities that help him *understand* music well.
There are many other things I try to do for my students, but these are some of the really important ones.
If your teacher is only correcting mistakes, perhaps it is time for a talk about your goals and where you are headed, as others have suggested.
pianoannie