I took ballet and with ballet you gain something called muscle memory and if you learn incorrectly, it's almost impossible to ever be a great dancer (because of muscle memory.) Because of this, you can't learn ballet out of a book or from a video -- you need an instructor to say "You're doing a great job" or "You need to do this instead."
Is learning an instrument online a bad idea because of the above reason or any other reason? I would like to learn the flute, but I live pretty much in the middle of nowhere. I see that there are plenty of learn flute online courses, but I'm wondering if anyone has had any success with learning an instrument over the Internet, out of a book, from videos, etc? I'm not talking about people who see an instructor and then go home and practice out of a book, but rather those who never have the help of an instructor.