he implicit contract is based on the needs (and also expectations) of the student not being too different from those for whom the class is intended. Private classes are designed to meet the needs of the needy students. The OP is a needy student, because of his over-preparation and high expectations. If the OP had gone into McDonalds and ordered a rare burger made with prime beef, and a whole-wheat bun, he'd have been told to go somewhere else for that meal. If he'd just ordered a burger, and expected prime beef, cooked less well, on a whole wheat bun, and them complained, he'd be laughed out of court. He did a lot of homework in advance of the class -- some might say too much -- but did not do any homework on the class itself. Big mistake.