Art Evolution: The main characters' appearaces (particularly the Bananas') changed practically every season.
The Artifact: The Bananas' teddy-chasing was the main point of the song it was based on, but in the series (the live-action one at least) teddy-chasing is rare, and is mainly confined to the early episodes of the series.
Clothes Make the Legend: Seriously, could you imagine the Bananas wearing anything but their blue-and-white striped pyjamas?
Cool Car: Not in the straight sense (the only thing going for it is the fact it's the only car in Cuddles Avenue) but Rat's Ratmobile does certainly look pretty cool.
Cultural Translation: When the series was exported to the US, the show's title card had to be spelt as "Bananas in Pajamas".
Deadpan Snarker: Morgan displayed this trait at times, most notably in "Lulu's Magic".
Early-Installment Weirdness: Early the show's first season, B1 and Amy had different voice actors, and in the case of the Bananas the voice actors were also inside the suits (though this practice was changed by the next season). The boing sound used when the Bananas get an idea was also completely different, there was no Rat, and Amy was missing her now-trademark bow as well as wearing the tutu that would eventually become a trademark of Lulu's.
Though it's not really recognisable, Taylor Owynns, who did the voice of Lulu, went on to be the female announcer for CityRail in Sydney. Yes Sydneysiders, that's Lulu's voice you hear when your train is pulling into the station.
Shane McNarama, who played the original Rat, went on to play the Camp Gay hairdresser Gino Esposito on Neighbours. Similarly, Nicholas Opolski, who played B2, played Evan Hancock in that show from 2000-2002.
Limited Wardrobe: Save for a couple of slight modifications here and there, all the characters on the show wore the same clothes in every episode.
Long Runner: The show has now been running for a total of twelve years, not counting the hiatus or its earlier incarnations as a song or thirty-second animated interstitial. It has been around for twenty years.
Never Trust a Trailer: Back in the mid-2000s, ABC1 transmitted a trailer for the show which featured footage hinting at a possible shipping between one of the Bananas and Lulu. Suffice to say, apart from the Romance Arc between the turtles Tolstoy and Thomasina (who ended up getting married in the 1999 season), there's no shipping between the main characters in the show. (Well, no intentional shipping on the creators' part anyway.)
Nice Hat: The rat's hat (of course), the Bananas' Beach Patrol visors and Morgan's legionnaire hat. The characters also wear many other nice hats which depend upon the context of the story.
No Antagonist: Subjectively Subverted. Though the Bananas and Teddies considered Rat in a Hat to be their friend, he often cheated them whenever he found a chance to, at least until one of the protagonists called him out on it. On the other hand, Rat in a Hat's status as antagonist is debatable as he never hurts any of the other characters, he just cheats or play pranks on them.
The Other Darrin: After Season 1, Ken Radley replaced Duncan Wass as B1 and Mary-Ann Henshaw replaced Sandie Lillingston as Amy.
Parental Bonus: The parental bonuses abound, resulting in the Periphery Demographic that watched the show in the Nineties. A good half of the names of all the barnyard animals count (here's the reason why Dolly the Sheep may have tickled some parent's funny bones) and there's also a turtle called... wait for it... Tolstoy.
Story Arc: Sometimes the live-action series would feature five-day-long story arcs which, when put together, would make a 25-minute episode. These include "Banana's Birthday" in 1992 and the five episodes chronicling the creation of a song and video ("Getting Rhythm", "Musical Stairs", "Swamp Lake", "Take One" and "Video Clip") in 1993.
The Trickster: Maggie the magpie (though she can't really help it, seeing as she is a magpie), and, to a slightly lesser extent, Rat.
Totally Radical: One week-long Story Arc in the 90s featured the Bananas and Teddies writing their own song before filming a music video for it. In one of the episodes Morgan is dressed in very M.C Hammer-like get-up and goes around saying "Cool, man! Cool!"