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.
"Oh, it's time to start livin'! Time to take a little from this world we're given!"
Evil Is Sexy: Fastrada, obviously. But to a lesser extent, Leading Player. Whether played by a man or woman his/her choreography is usually quite sexual, not surprising since this show was originally directed and choreographed by Bob Fosse.
Nightmare Fuel: "Glory" is a juxtaposition of catchy music and surreal gore that can be extremely unsettling when handled skillfully.
One-Scene Wonder: Berthe is in one scene and has one song. And yet her song is among the most famous in the musical, and she often gets the most applause at curtain calls.
More precisely, Berthe is in only one scene, but the player who acts the Berthe part may appear briefly at other points (such as the graduation scene) and joins the rest of the troupe for the Grand Finale.
Andrea Martin's turn as Berthe in the revival was so great that they gave her a line in "Magic To Do"... specifically "Humor, handled by a master".
Surprise Creepy: Depending on what you think of the earlier parts of the show, the Lead Player's behavior towards Catherine when she first appears and the entire Finale may be shocking and unsettling.