Critical Research Failure: "I'm a gypsy on my own!" is one in-universe, the whole point about "gypsies" (i.e. the Romani) being that they're an ethnic group, not a lifestyle choice.
Executive Meddling: Zappa planned to release the album around the 1967 Christmas holiday, but was held up due to the album cover. Paul McCartney was said to not have any problems with Zappa parodying the Sgt. Pepper cover, but Capitol wasn't too thrilled and only allowed the use if the cover was reversed, with the inner artwork being placed on the outside and vice versa.
To make matters worse for Zappa, MGM censored some parts of the album, the most absurd of those being the suits thinking that the "apron and her pad" line in "Let's Make The Water Turn Black" involved sexual activities instead of a regular waitress apron and order pad. Zappa restored the censored bits in the 1987 remix and most of them make an appearance on the 1995 remaster.
"Funny Aneurysm" Moment: The cops shooting the hippies a couple of years before Kent State. This is one of most widely cited musical examples. Younger listeners might also think of the police treatment of the Occupy movement.
Hilarious in Hindsight: Eric Clapton claiming he sees "God" on "Nasal Retentive Calliope Music," since this would later become his nickname.
The line about a hippie going to get crabs in "Who Needs The Peace Corps?" becomes much more funnier after family restaurant chain Joe's Crab Shack released psychedelic t-shirts promoting "Peace, Love and Crabs", blissfully unaware of the potential double entendre related to the album.
Hype Backlash: A key moment that led to the creation of this album was when Zappa went to check out the music scene in San Francisco and came back unimpressed, feeling that the music wasn't as revolutionary as they claimed.
Throw It In: The word discorporate is explained at the start of the song "Absolutely Free".
The track "Telephone Conversation" is a piece of a telephone conversation (Exactly What It Says on the Tin) that Zappa recorded between Pamela Zarubica (the original Suzy Creamcheese from the album Freak Out!) and a friend of her, Vicki , who claimed that Pamela's father was looking for her and had called in help from the FBI. Apparently the FBI was threatening to arrest Vicki for withholding information. Zarubica called her back to discuss matters and Zappa recorded the conversation including a 45 second snippet that made it on the album.
Some photographs on the album cover were taken from Zappa's high school yearbook.
What Could Have Been: Originally the album was going to be called "Our Man In Nirvana". Zappa changed the title and the concept when he heard about the Beatles "Sergeant Peppers Lonely Hearts Club Band" hype.