* BookEnds:
** A variation applies regarding Debbie Gibson. The final Casey Kasem-hosted show of the original ''American Top 40'' (August 6, 1988) featured the teenage pop star at #40 on the ''Billboard'' chart, falling nine notches with her former #1, "Foolish Beat." The first installment of ''Casey's Top 40'', aired the weekend of January 21, 1989, featured another Gibson song in the #40 position: "Lost in Your Eyes," which debuted at #40 on the ''Radio and Records'' chart and would hit #1 six weeks later. (Both songs hit #1 on both ''Billboard'' and ''R&R''.)
** That final 1988 show included a song by Music/TheMoodyBlues in the top 40 ("I Know You're Out There Somewhere", which also stayed put for the first Shadoe Stevens-hosted program), as did the July 4, 1970 debut show ("Question").
* ChartDisplacement: Happened quite a bit in the 1990s, because ''Casey's Top 40'' used the ''Radio and Records'' CHR Top 40 chart instead of the ''Billboard'' Hot 100, and he kept using it when he returned to ''American Top 40''. That meant that songs that were huge, inescapable radio hits that were deemed ineligible to chart on the Hot 100 due to rules on physical single release made it onto Casey's chart. Likewise, several songs that made it onto the Hot 100, but not into its Top 40 were included on the ''Radio and Records'' chart. This meant that an artist would have a completely different track record on Kasem's show than what's in Billboard's archives.
* ClusterFBomb: Creator/CaseyKasem was known for attention to detail and perfection, and he would become annoyed or sometimes outright angry if something didn't go right. This was played to perfection in September 1985, when taping an episode that had what's been referred to by fans as the "Dead Dog Dedication." In that episode, the uptempo dance song "Dare Me" by Music/ThePointerSisters was to be followed by a Long Distance Dedication from a listener wanting to eulogize his beloved pet dog (which had recently died) with the ballad "Shannon" by Henry Gross[[note]]Long assumed to be about a dog that was swept out to sea, it really was inspired by Gross' dog, who was very much alive. The one who had died was Shannon's original owner, Gross' wife Kathleen.[[/note]] As Kasem[[note]]well known as a lifelong animal lover/animal rights activist and vegan[[/note]] was reading the letter during the original take, he snapped and went into a profanity-laced tirade (including several f-word utterances) about how he believed a song about death was inappropriately slotted after a dance song. Kasem later calmed down and re-recorded the take, and of course the rant never made it to air, but the original take was preserved on tape and circulated among engineers for years. It later became popular through bloopers specials and sites such as Website/YouTube.
** Of course, this is not the only time Kasem lost his temper while taping [=AT40=]. Another clip circulates on Website/YouTube where he became irritated at having to record individual station promos for station affiliates, believing it to be a waste of time. Included between takes were several words and commentary about the towns served by the affiliates fit only to be heard by a sailor.[[note]]In [[http://www.negativland.com/archives/009interviews/for-the-record.html an interview with For The Record]], Negativland's Mark Hosler spoke about the time Creator/DrDemento told him he'd worked in the same studio as Kasem, ''and that was the way Kasem acted all the time.''[[/note]]
*** There's also the outtake where he objects to the detailed biography of {{Music/U2}} he was given to read when "Pride (In The Name of Love)" hit the Top 40. "These guys are from [[ArtisticLicenseGeography England]] and who gives a sh*t?!" Immortalized in Music/{{Negativland}}'s "[[https://www.youtube.com/watch?v=Z6gPSSYxex0 The Letter U and the Numeral 2]]", which is a sampling of this and the previously mentioned rants (along with other Kasem ''[=AT40=]'' voice clips) set to an intentionally-crude instrumental rendition of "I Still Haven't Found What I'm Looking For", and yes, [[https://en.wikipedia.org/wiki/Negativland#U2_record_incident Negativland got in hot water for it]] (though oddly by U2's label Island Records, and not by Casey or any of [=AT40=]'s rights holders).
* DuelingShows: Rick Dees' ''Weekly Top 40'' and, ironically enough, ''Casey's Top 40'' in the early 1990s. For the MusicVideo side of things, ''Top 20 Video Countdown'' for ''America's Top 10''.
* HeAlsoDid: The tiny closet-sized studio where the show was taped in the first part of TheSeventies featured furnishings made by Creator/HarrisonFord, back when he still had a day job as a carpenter.
* KeepCirculatingTheTapes:
** The entirety of Shadoe Stevens' run is apparently intact, but the rights are not owned by Premiere Radio Networks alongside Casey Kasem's episodes, instead being owned by Cumulus Media (interestingly enough, now owners of Westwood One, rights holders of ''Casey's Top 40''). This explains why the [=iHeartRADIO=] app doesn't broadcast Stevens-era episodes on its ''Classic American Top 40'' channel, though Stevens himself [[https://www.youtube.com/watch?v=QcvQw8dTP7s uploaded a video]] to his own personal [=YouTube=] account stating episodes had been remastered and were ready for packaging a la ''Casey Kasem's American Top 40: The '70s/'80s'', so they may soon appear elsewhere.
** The majority of Casey Kasem's second run on the program (1998-2004), although the charts themselves from 2001 onward are available on the countdown's website. Unlike the Shadoe Stevens example above, however, [=iHeart=]'s ''Classic American Top 40'' channel has aired three episodes from this period as "special broadcasts": an edition dealing with the top artists of the '90s, a special "[[MillenniumBug Y2K]]" edition dealing with "40 Days That Changed Music" that originally aired on New Year's Day 2000, and Kasem's final broadcast from January 4, 2004.
** Also extends to the whole of ''Casey's Top 40'', which, according to Westwood One, is completely ''gone'' aside from circulating copies. Episodes of all three mentioned versions can, as always, be found on [=YouTube=].
** Charis Music Group, founded by Shannon Lynn, is the company in charge of remastering the original episodes for rebroadcast (i.e. ''Casey Kasem's American Top 40: The '70s/'80s'') and has the entire original run of ''American Top 40'' (1970-95), as well as the entire run of ''Casey's Top 40'' (1989-98), available for purchase from their website/[=eBay=] store. This is probably the closest anyone will come to being able to purchase ''[=A/CT40=]'' episodes from an official source, but be warned -- if you're going for complete runs (the entire Casey Kasem era, the Shadoe Stevens era, etc), it will set you back a pretty penny (though individual episodes are also available if you message the owner).
* MarathonRunning: The year-end Top 100 countdown shows were broken into two four-hour parts, which could be played on separate days, or as a single eight-hour show. Many stations elected to do the eight-hour version, usually running it on New Year's Eve. From 1983-1991 and 1993, the default format of the year-end show was 8 hours, with instructions to radio stations on how to cut them into two 4-hour parts.
* MilestoneCelebration: The 20th Anniversary Special, aired the weekend of July 7, 1990. A break from the traditional countdown format, the special detailed highlights and played selections of songs from each year ''[=AT40=]'' was on the air up to that point (1970-1990).
* MissingEpisode: The master tape for the final hour of the second-ever episode (July 11, 1970) has disappeared. In 2016, radio producer Ken Martin re-created a third hour of the show, using bits from [=AT40=] shows from July and August 1970; the show aired on several radio stations as part of the "[=AT40=]: The 70s" package.
* MoodWhiplash:
** In radio parlance, a "train wreck" transition is where one song of a particular style is played after another song of a completely different style, for instance a soft, light-hearted ballad played before or after a hard rock song. Radio programmers strive hard to avoid these unless impossible to do so. In any given week's show, one or more of these transitions were part of the show ... inherently so, because often a ballad listed at, say No. 24, might be followed by a hard rock song at No. 23. While sometimes Casey or the producers would break up the potential transition with a commercial or playing an extra (using a song of an in-between style, to bridge between, say, the ballad and hard rock song), many other shows have been unable to avoid this beyond an occasional number {{Jingle}} or failing that, Casey just segueing into the song.
** In some markets, ''[=AT40=]'' was heard not on the local Top-40 station, but on a station that played primarily adult contemporary, middle of the road, or album rock music. Depending on the composition of that week's Top 40 records, that would have put a station whose primary music format consisted of Music/BarbraStreisand or Music/BarryManilow in the position of playing a Music/PatBenatar or Music/LedZeppelin song (or vice versa) - that is, assuming said station did not delete the records that didn't fit its playlist from the show (which stations had the option to do). Regional differences and other variations within the Top-40 format itself likely also accounted for similar disconnects between the content of ''[=AT40=]'' and local affiliates' playlists. For example, memos archived by [=''AT40''=] historian/expert Pete Battistini illustrate that as early as 1973, some affiliate stations in predominantly white areas had concerns about the amount of Soul[=/=]R&B played on the show that did not become mass-appeal hits outside heavily Black or Hispanic markets.[[note]]One concern along that line was that it always seemed like there was a Music/JamesBrown song in the first hour, because most of his hits in that era tended to cross over onto the pop chart but peter out somewhere in the [=30s=] or upper [=20s=], and the non-R&B stations worried that listeners wouldn't care for his famously loose style where a song would feature little more than an EpicRiff and Brown ad-libbing the lyrics and switch stations.[[/note]]
** The reason behind Kasem's infamous "Dead Dog Dedication" tirade while taping the September 14, 1985 show. When he realized, during taping, that he had just played the uptempo dance song "Dare Me" by the Pointer Sisters and now was being asked to play the mournful ballad "Shannon" by Henry Gross as a Long Distance Dedication ... he completely lost it. He apparently lost his patience with his staff constantly slotting songs -- especially extras -- in such a way that "train wreck" transitions were becoming too common, and that playing a narmish ballad after an uptempo dance song was simply inappropriate. In the end, Casey calmed down and delivered a take as intended, but rarely were two songs of completely different styles played before or after one another unless it could not be avoided.
** On the February 4, 1984 show, an uptempo dance hit - Shannon's #14 record, "Let the Music Play" - was immediately followed by a story about the recent passing of R&B legend Jackie Wilson, who had died a few weeks earlier after spending nearly a decade in a coma precipitated by a heart attack.
* PromotedFanboy:
** Current host Ryan Seacrest was a loyal superfan of ''American Top 40'' as a child in the 1980s.
---> '''Ryan Seacrest''' (in an interview with People)''':''' When I was a kid, I would listen to Casey Kasem’s ''[=AT40=]'' show every weekend, and dream about someday becoming a radio DJ. So when decades later I took over his ''[=AT40=]'' countdown show, it was a surreal moment.
** One of the show's engineers near the end of Casey's original run and retained into the early [=CT40=] years, Guy Aoki, would previously write into the show a few times before getting hired.
* ShortRunInPeru: In July 1994 ABC Radio pulled ''American Top 40'' from its affiliates and replaced it with ''The Rick Dees Weekly Top 40'', meaning that the final six months of Shadoe Stevens' hosting stint were only heard outside the US.
* ScrewedByTheNetwork: ''American Top 40'''s production company, Watermark, was purchased by ABC Radio in 1982. Much of the reason ''[=AT40=]'' went off the air in 1995 was because it was getting beaten in the ratings by ''Casey's Top 40'' and ''The Rick Dees Weekly Top 40''. But both of those shows existed because of questionable moves by ABC regarding ''American Top 40''. When ABC insisted that ''[=AT40=]'' affiliates start airing other ABC shows and commercials, many of them dropped the show. One of the stations, KIIS-FM in Los Angeles, had their morning DJ Rick Dees start his own countdown show, which soon went into syndication and was quickly picked up by other former ''[=AT40=]'' stations. Then when Casey Kasem's contract came up for renewal in 1988, ABC (who reportedly was eager to bring in a younger host) turned down his salary proposal, so Kasem left to start another show.
* UncreditedRole:
** No one involved with the show's {{jingle}}s and music beds was credited for most of the run (this would become common practice for most shows aping the format during the 1980s, though most of them used JAM much like AT40). It wouldn't be until the mid-90s near the end of ''Casey's Top 40'' that JAM Creative Productions would receive acknowledgment for their work, only for the revival to go back to leaving the producers ([=ReelWorld=]) out of the credits. It wouldn't be until well after the fact that anyone would be able to figure out, let alone get confirmation, as to who did which package.[[note]]information of which can be found on the main page[[/note]]
** TM Studios' involvement on the show plays with this a bit. Their work on the original run as music producers were, like JAM, Firstcom and HLC after them, uncredited. The studio, under the TM Century name, would get a specific "Some of the music heard on Casey's Top 40 comes from TM Century [=HitDiscs=]" credit for their edited versions of the songs starting late into the ''[=CT40=]'' era (when these edits were first utilized) into the revival.
* WhatCouldHaveBeen:
** While the show steadily gained new affiliates and listeners in its first two years, it was still losing money. In the summer of 1972, the top brass at Watermark Productions held a meeting where they discussed the show's future, with several of them (Casey Kasem included) leaning toward ending the show. It was only after they saw some budget projections indicating that they were just a few months away from turning a profit, that they backed off and decided to keep going.
** ''Weekly Top 40'' host Rick Dees was reportedly interested in taking over as host of the current version following Casey Kasem's 2004 departure, but Premiere Networks, wanting to give the show a complete makeover, went with Ryan Seacrest instead.
** Casey Kasem introducing "Rapper's Delight" by Music/TheSugarhillGang on the countdown would've been a truly historic moment: an icon lifting the curtain on a new era in pop music. Unfortunately, it never happened. "Rapper's Delight" only spent two weeks in the Top 40. The first week, the regular countdown was pre-empted for a "Top 50 Hits of TheSeventies" special countdown. The second week, Casey took the week off and substitute host Mike Cleary was the one who got to make the announcement.
** Casey might have ended up working for Westwood One (producers and distributors of ''Casey's Top 40'') as early as 1982, as Westwood One was said to be one of the parties interested in purchasing [=AT40=] production company Watermark. In the end, Watermark sold to ABC, who proved to be quite aggressive in getting new affiliate stations - including pulling the show off non-network affiliates in certain markets.
*** For example, in Chicago, [=AT40=] was heard during the very early '80s on CBS-owned WBBM-FM. After ABC's purchase of Watermark, ABC had the show moved to their owned-and-operated 50,000-watt giant WLS-AM (which by then was fading in popularity due to competition from FM stations, including its sister WLS-FM station). After WLS-AM dropped its Top 40 format in 1987, ''[=AT40=]'' was heard exclusively on WLS' FM side (by then known as WYTZ/Z95). WBBM-FM (B96) would regain Casey in 1989 when the station became a ''Casey's Top 40'' affiliate.
** The revival of ''[=AT40=]'' was almost a Westwood One production. When the rights for the ''[=AT40=]'' name reverted back to Casey Kasem in 1997, he offered Westwood One the use of the name as a rename for the existing ''Casey's Top 40''. Westwood One refused this offer, setting the stage for the ''[=AT40=]'' revival on AMFM syndication, which was soon after folded into what is now iHeartMedia.
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