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.
Big Lipped Alligator Moment: "Rhythm of Life." Appears, is awesome, and is never referred to again. The Movie gave it some relevance, as Oscar is seen getting over his neurosis while hiding in a tire after the church runs from the cops, but that scene is not in the original play.
Memetic Mutation: The first few bars of "Hey Big Spender" is the theatrical equivalent of the first few notes of Beethoven's 5th.
One-Scene Wonder: Daddy Brubeck, (Sammy Davis, Jr. in The Movie) who sings Rhythm of Life and is never heard from again, yet his song is one of the most famous in the show.
Superfluous Solo: "Too Many Tomorrows". The minor character Vittorio inexplicably has this long, slow, boring solo right after Charity's dazzling showstopper "If My Friends Could See Me Now". It has nothing to do with the plot, and he sings it to a thoroughly unimportant character. Notably, this song was removed from the movie.