These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Strawman Has a Point: Madame Natasha is paid to teach students ballet, which includes teaching them how to follow designated choreography. Kristen's improvisations could look like mistakes to a conservative or traditional ballet critic. Changing the steps every time would be frustrating for a director, not to mention difficult for other dancers to adapt to when she isn't dancing solo.