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.
YMMV: American Idiot
Arc Words: Inevitable, given the storytelling aspect of the album, but a few stand out, especially in 'Homecoming'. Part 2 bears resemblance to the 'I don't care' part of Jesus of Suburbia, acting a bit like Book Ends as JOS returns home. Also, Whatsername's 'Nobody likes you' taunt shows up quite a bit, possibly to imply thoughts going around JOS/ Jimmy's head during the song.
Big Lipped Alligator Moment: The "Rock and Roll Girlfriend" bit of Homecoming doesn't make sense in the album's context, and was never mentioned before or after the song. It makes more sense when you realize it's about Tre's life, but it still doesn't really fit in with the rest of the album.
For a few years after its release, several older and more hardcore fans tried to play the entire album off as a BLAM within the band's career. As we can plainly see, It Got Worse.
Genre Deconstruction: Of the Punk movement as a whole. JOS becomes a self-absorbed, self-destructive rebel without a cause who ultimately accomplishes nothing and according to "Letterbomb" is the real American Idiot. This creates the interesting social commentary in that rather rather than turning people into mindless drones, the alienation and paranoia of modern American society creates self-destructive rebellion.
In the musical it gets a little more explicit - while JOS and Whatsername serenade each other, Jimmy leans mournfully over the balcony and sings to JOS,
I text a postcard, sent to you
Did it go through?
Sending all my love to you.
You are the moonlight of my life every night
Giving all my love to you
It could likely be interpreted as JOS' thoughts/feelings about Whatsername at the time, considering the Double Consciousness interpretation.