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.
Awesome Music: Aquarius; Hair; Walking In Space; Let The Sunshine In (The whole score, really.)
Best Known for the Fanservice: The famous nude scene lasts for merely twenty seconds and is so dimly lit that one critic quipped, "I couldn't even tell if any of them were Jewish". Yet it's the most talked-about scene in the show, leaving people who haven't seen it with the impression that the ENTIRE show takes place with the actors naked.
Breakaway Pop Hit and Covered Up: The show produced four popular singles— the title song by The Cowsills, "Starshine" by Oliver, "Aquarius" by the 5th Dimension, and "Easy To Be Hard" by Three Dog Night.
Genius Bonus: The opening vocal line of the song Sodomy is the titluar word sung on an upward arpeggio of the 5th scale degree, a root, and a 3rd. Or, in solfege, sol-do-mi...
Ho Yay: Deliberately written into the show itself, which provides quite some subtext between Claude and Berger at times.
Supporting character Woof: "I'm not a homosexual or anything, but I would make love to this man" (Mick Jagger). Bordering on Transparent Closet. Lampshaded by Jeanie, who points out that Woof is 'hung up on' Claude.
Also a Les Yay: In "White Boys," the last appealing trait of white boys listed is that they're "Beautiful like girls." (Note this is being sung by black girls.)
Tear Jerker: If "The Flesh Failures" can't make you tear up, nothing will.
Adaptation Displacement: The film was made in 1979 after the hippie movement was considered to be over, synth music was king, and Reagan was about to be elected. As such it was felt to be anachronistic at the time since it felt like a product of the early '70s, and didn't make too great an effort to "upgrade" the message of the movie, and only slightly "disco-ized" the original soundtrack. This is fortunate for the film's rewatchability, however, today, since the musical's original message and milieu can still be considered relevant today whereas Disco is Dead. At the time of the release, however, it was viewed as hopelessly retro.
Awesome Music: The brief solos by Renn Woods ("Aquarius"), Nell Carter ("Ain't Git No") and Betty Buckley ("Walking In Space").
An oddly specific example in addition to above: the funky bass rhythm stylings of Wilbur Bascomb are considered definitive by bass aficionados.
Broken Base: Opinions on the film among fans are sharply divided.
Ho Yay: In addition to the stageplay's lingering Ho Yay, it's all over the place with the draft board, and the general seems to enjoy watching his men perform their routines.