Great concert pianists do not always become good piano teachers—especially for beginners. A good piano teacher is patient, makes the complex simple and allows the student to progress at his or her own rate. That is why you want your meditation teacher to be more like a good piano teacher and less like a concert pianist.
Similar to the concert pianist, there are many meditation practitioners who have mastered inner states of peace and calm but are not very good teachers. Because meditation has come naturally to them, they do not understand what the beginner is going through. They simply sit and meditate at an advanced level and ask the beginner to do the same.
Could you imagine what a piano lesson might look like if a piano teacher did the same? He would start playing at his level and then want the student to follow. “These are the keys, these are the notes, and here is how you play piano concert number two by Rachmaninoff. Now you go.” Only prodigies would be able to replicate. The same is true of meditation. When advanced meditative states are displayed, only a select few can follow. Only when you have advanced in your meditation practice does it make sense to take classes with advanced practitioners.