Re: how many back talk would you take?
Unless you are a teacher who tries to protect your reputation for quality, work on your problem, not the others.
If you try to correct somebody else be ready to accept the fact that most will not listen but do not be offended by this. You can't change people's attitudes but what you can change is how you react to them. For me I also think for these kinds of people, why should I give them readily the secrets I know when I discovered them only after 15-20 years practice. They weren't handed out to me I worked for it. They should work for it and discover these by themselves, so everything's fine. They dont want to listen, fine by me.