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.
Cry for the Devil: The three ballads are used effectively in this way, but the one that seems to get the audience's sympathy most is "The Ballad of Czolgosz", where assassin Leon Czolgosz's motivations are stated clearly: he was a lonely man, who all throughout his life had lived in poverty and misery for reasons beyond his control, so he killed big business president Bill McKinley to "take control of his fate".
Ear Worm: And it's seriously a problem. "What a wonder is a gun! What a versatile inveeeeeention!" Do not see before working with first graders and/or getting on a plane.
"How I Saved Roosevelt" is another one you don't want to sing in public - "Too cold for the stomach in Washington/I go down to Miami, kill Roosevelt!"
And, of course, you do not want to get caught singing, "C'mere and kill a President..."
Nor do you want to be caught going "Damn you Lincoln, you righteous whoooooooooore!"
Everybody's got the right to some sunshine/not the sun but maybe one of its beams...
The Ballad of Guiteau counts, too. Look on the bright side, look on the bright side...
In the USA you can work your way to the head of the line...
Nightmare Fuel: The end of Lee Harvey Oswald's scene, when all the assassins surround him singing about how much they admire him while he loads his rifle and prepares to shoot Kennedy. The Lyrical Dissonance and the menacing sound of the melody make it especially creepy.
One-Scene Wonder: Depending on the direction, The Proprietor may pop up throughout the rest of the show, but he's only scripted for the opening scene, leading "Everybody's Got the Right". In the original production, Lee Harvey Oswald was this as well, though ever since the 2004 Broadway revival, it has become common practice to double him with The Balladeer.
Tear Jerker: "Something Just Broke", the one truly honest and heartbreaking song in the show, about the everyday aftermath of an assassination.
Booth's solo in "The Ballad of Booth" qualifies, as well.
The reprise of "Everybody's Got The Right" was one in the original production.
Czolgosz's portion of "The Gun Song," where he meditates on all the men who labored in factories or mines and were injured or killed just to make a simple object which in turn will be used to kill more people.
Wham Line: Most of "The Ballad of Booth" paints John Wilkes Booth as having a legitimate grievance against Abraham Lincoln, and might even garner some audience sympathy...then, near the very end of the song, he calls the President a "Nigger lover," and suddenly we realize how much of his hatred was motivated by racism.
An in-universe example from "Something Just Broke": "The president's been shot..."