Don Giovanni/YMMV

Alternate Character Interpretation: Is Anna a dutiful daughter who cares more for the honor of her dead father than her own happiness, or does she secretly feel passion for Giovanni and then self-loathing once she realizes that he killed her father? Is Zerlina a romantic ingenue thinking Giovanni is her Prince Charming before realizing the truth or a coquettish girl that wants Giovanni because he promises her instant marriage (and, by virtue of that, his wealth and title)? Is Masetto a concerned fiance who feels helpless in his supposed inferiority to a nobleman in the eyes of his own fiance or a paranoid jerkass? The others as well, but these three most of all.
- The idea that Donna Anna is in love with Don Giovanni and was willingly seduced by him has been standard for so long that simply believing that she was raped/almost raped comes across as Alternate Character Interpretation.
- Even the title character has received some of this over the years. While in Mozart's time as well as today, Don Giovanni is considered an Affably Evil Jerkass, in the mid-19th century, at the height of Romanticism, Giovanni's unfettered attitude toward sex and life caused him to be interpreted as a Byronic Hero. Consequently, Donna Anna was seen as a Moral Guardian who was only after him because he violated the social order of the time. Never mind the fact that, you know, Giovanni killed her father...
- Another for Don Giovanni: is he a young man with a comically over-the-top list of "conquests" that averages out to roughly one a night since he was in his teens, or is he an older man whose seductions were slow and spread over many years, and who is desperately trying to return to the excesses of his youth? Directors can make the story considerably more comic or darker simply by altering the (perceived) age of the lead singer.
Crowning Moment of Awesome: "Long live women; long live good wine -- sustenance and glory of humanity!" -- in context, sung heartily to a broken Elvira, it makes Giovanni sound like a total Jerkass... but definitely one with guts. Also "Don Giovanni! to dine with thee I was invited... and so I've come!" and the Don facing the stone guest unflinchingly. In fact, the whole dinner scene, from start to finish.
Crowning Music of Awesome: Mozart's wife Constanze claimed after his death that he had considered this opera his best work. That alone should tell you something.
Draco in Leather Pants:
- Some productions do this to the Don, inevitably. Let's put it this way: if there were fanfics about opera, Giovanni's entire persona would no doubt be hiding a vulnerable romantic trying to find his One True Love.
- This was also quite common in romantic-era criticisms of the opera, which saw Giovanni as a Byronic Hero who was a model individualist, and often derailed Donna Anna into a Moral Guardian who only hated Giovanni because she hated/was ashamed of sex (totally disregarding the fact that Don Giovanni also killed her father).
Ear Worm: The act 1 duet between Zerlina and the Don, La ci darem la mano (There we will entwine our hands).
- Which will never sound the same again once you've noticed its resemblance to The Lumberjack Song.
  - Now it is far too late to try singing Ah, pietà signori miei to the Monty Pythons
Evil Is Sexy: Giovanni may be an example of the fact that Aristocrats Are Evil, but the princesses on the list would hardly be only after his lesser wealth...
Magnificent Bastard: As close to a definition of the trope as you'll get or need.
The Scrappy: Don Ottavio. Was even included in a recent BBC Music magazine list of operatic Scrappys.
Values Dissonance: These days, Elvira's one wild night of passion with Giovanni wouldn't ruin her chances at marriage.
What an Idiot!: Masetto and Elvira fall victims to this during Act 2, immediately trusting that "Leporello" (the Don in disguise) is perfectly willing to kill his master (having been loyal until then) and that "Giovanni" (Leporello in disguise) is now quite ready to repent by marrying Elvira (disregarding the famous Catalogue Aria, which went through the Don's entire M.O.).