- Awesome Music: It's Verdi, after all.
- Broken Base: Opera fans are split on whether the opera should be performed in French or Italian. The French words are the words Verdi originally set, and the Italian translation is sometimes awkward, but many of the best Verdi singers sound more comfortable in Italian than French.
- Follow the Leader: The political part of the plot concerns Carlos supporting the Dutch rebellion against his father who is about to send the Duke of Alba to crush it. Reliable sources tell that this essential plot thread - a rebellious son who supports a rebellion against his father - inspired George Lucas when he hatched the plotline of Star Wars in 1977.
- Ho Yay: Carlo and Rodrigo. There's just so much hand-holding and hugging and declaring things like "we shall live together and die together". And then Rodrigo dies in Carlo's arms. (Especially strong in the Met version with Alagna and Keenlyside, and the Salzburg production with Kaufmann and Hampson.)
- Tear Jerker: the scene of Rodrigo's death and Carlos and Élisabeth's farewell duet can sometimes make singers teary-eyed. On stage.
- The Woobie: Carlos may be a poster image for this trope.
YMMV / Don Carlo