My job as a music teacher is to tell my student what is wrong with her performance, make sure she understands how to correct it, and then send her away to drill on her own, or supervised by her parents or nanny. Later, I will see her again, and find out whether her practicing has been fruitful.
My job is NOT, contrary to the opinion of the mother of my newest student, to supervise her drilling a song for half an hour. Especially not when the student is barely seven years old, is only having a few lessons to learn ONE song to sing for a special occasion, and can already sing the song perfectly. I made a decision to cut the lesson short, even though the nanny was there and I couldn't talk to the mother. Irate mother called me later and asked why I didn't give her child the full half-hour as agreed. Because I was paid to teach her one song, and she learned it! Why punish her by making her repeat it until she hates it?
Said mother also thinks that half-hour lessons are awfully short. Not for a one-on-one lesson with a small child, they're not! When you're seven, half an hour is a really long time. I'm glad that I will not be teaching this child for long, even though I could use the money. The kid is great, but the mother...yeesh!