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.
YMMV: The Pirates of Penzance
Ear Worm: Quite a large number, but by far the most well-known is: "I am the very model of a Modern Major-General..."
Values Dissonance: Frederick's "slave of duty" mindset will tend to strike modern audiences as merely silly. Englishmen of Gilbert's day, though, would have recognized it as a parody of their own code of conduct.