Monkeeeey,
I second what Duveldrinker says - based on what you've said, go and find yourself another instructor who cares about your progress. You are the customer, you deserve better!
Duchess driver, not sure that "Always end with the positives" is universally true. I sometimes end on negatives, or emphasise the negatives over the positives, if the student needs to be brought down a peg or two (e.g. thinks they are better than they actually are) or is not putting in the effort. I don't do this regularly, but doing it very occassionally can, with some students (but not all), make them go away and think hard about what their doing, and show big improvements next lesson.
FFF
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