I love Kat’s observations here. I’m very much an advocate for allowing students to make mistakes. I find students get frustrated when they try something new and the body doesn’t quite know how to handle it yet. Often I find that they try something and the voice will break and that break then drives them back into doing things in their habitual way.
At these times I remind the student that they’ve been locked into their habit for a long time, so it might take us a long time to retrain or remove that habit. We just have to give the body time to work it out and trust the exercise and our bodies.
However, sometimes that frustration also creates an opportunity to try a new tactic. Change the conditions of the exercise (or trying a new exercise entirely) whilst still striving for the same result. I did this just yesterday with a pupil and the lesson ending in such a positive way compared to our previous lesson.
One other issue I find is that frustration often comes when someone is doing an exercise for the sake of doing an exercise. If you clarify what the exercise is doing, slow the student down and get them to really think about what they are doing, then they are much more likely to do better with the exercise and make a positive change that is then reflected in their attitude.