"Lyre, Lyre, Hearts on Fire" opens with Xena, Gabrielle and Joxer breaking into a rendition of Edwin Starr's War and spends the rest of the episode having two warring parties fight it out in a battle of the bands rather than with swords. This episode followed up right after several very serious episodes too.
"Married With Fishsticks", which mostly forgets about the story arc going on at the time to do a pointless filler episode where the feuding Aphrodite and Discord accidentally send Gabrielle into an alternate world where she's a mermaid, and is entirely populated with merpeople. The whole thing is incredibly weird, and ends with it apparently being All Just a Dream as Gabrielle wakes up back with Xena.
Given that this was in season 5, it's noted on the DVD special features that everyone was quite wary that this not be the show's 100th episode.
Draco in Leather Pants: This trope's even funnier when you realize there really IS a guy named Draco in Xena, and that he DOES wear leather pants. The show even plays the trope straight after everyone was suddenly made to love each other by Cupid's playful son, who somehow got a hold of daddy's arrows. The effect was later reversed, except for Draco. Xena suggested Cupid not undo this one to make the warlord a better, less dangerous-to-society person. This comes back to haunt them in a later episode.
Evil Is Sexy: Callisto and Ares. Well, everyone is sexy in this series, but the villains tend to be sexier than the average peasant.
Foe Yay: Xena and Callisto, Xena and Ares, Gabrielle and Ares.
In the early season one episode "Cradle of Hope", Gabrielle scorns the idea of someone sending a baby down a river. Then came the season three episode, "Gabrielle's Hope", in which Gabrielle sends her (evil) newborn baby down a river rather than kill her — an act that comes back to haunt Xena and Gabrielle in a big way.
The many deaths of Joxer who died permanently in season 5.
Ares falling out of the sky after Gabrielle accidentally depowered him. Sadly, Kevin Smith died in kind of the same way.
Harsher in Hindsight: In "Remember Nothing," Xena is finally driven to take back her wish upon seeing Gabrielle kill someone. Congratulations, you've saved your partner's innocence...for a whole one year.
He Really Can Act: Hudson Leick played bit parts in soaps and never really garnered any attention... until she played Callisto. The range and depth of her acting as well as her development of the character was just insane (... as in insanely awesome). When she had to play Xena for a couple of episodes (Makes Sense In Context) she was jaw-droppingly good, and she played one of the most complex and heart-rending villains to ever grace the television screen without dropping a beat. It was her acting as a reformed Callisto that justified the entire existence of the "Xena and Gabrielle die and become angels" plotline.
My Real Daddy:Although John Schulian created the character in Hercules for the episode The Warrior Princess his Xena was more of a Femme Fatale and then a Distaff Counterpart to Hercules. It was the head writer for Xena, RJ Stewart who refined the character as we know her.
Narm: Livia/Eve's bad acting causes this. When she's angry she sounds less like Rome's champion and more like a Valley girl.
Never Live It Down: Gabrielle's insufferable flirting with complete pacifism. More specifically, her starting it by throwing Ephiny's staff into a river, which comes off as quite callous considering what a big moment her getting it was. Actually that's not correct. The staff Ephiny gave her was sliced in two at the battle of Troy, in the first season episode "Beware Greeks Bearing Gifts."
Retroactive Recognition: This show provided a stepping stone for many now-familiar faces in the science-fiction circuits, such as pre-Roswell Shiri Appleby, pre-Firefly Gina Torres, pre-Farscape Claudia Black, and pre-Hellboy Selma Blair. There was also an early appearance from Kathryn Morris of Cold Case fame, and Manu Bennett almost a decade before his roles in Spartacus and Arrow. And of course, Karl Urban, who played no less than four different characters across the first five seasons.
Scapegoat Creator: Fans complained loudly and often about Season 5 at the time, usually blaming new show-runners Alex Kurtzman and Roberto Orci for everything. Apparently, it wasn't just the fans who felt this way, as Kurtzman and Orci were suspiciously gone about halfway through the season. While being show-runners made them responsible for many creative decisions, they nonetheless still had to answer to Rob Tapert. The series was also hurt by The Lord of the Rings's production, as a number of experienced, local personnel left to work on the big-budget trilogy.
Seasonal Rot: Season 5 is generally regarded by Xena fans as when the show went downhill, season 6 fares even worse.
Special Effects Failure: Some of the CGI and blue-screen effects used in the earlier episodes (such as in "The Titans", "Prometheus" and "Mortal Beloved") have not aged well. Somewhat justifed, as the budget wasn't exactly high.
Strawman Has a Point: The gods in the "Twilight of the Gods" arc. They are trying to take 1 life in order to save their families and the beings they love at the very least (putting aside their responsibility to humanity and their godhood). Considering that we already established that if Eve had died as a baby, she would have gone straight to Heaven or the Eleysian Fields, to eventually be reincarnated - something that the Gods know and are very familiar with - from the Gods' perspective you can see exactly why killing her seemed reasonable.
The Woobie: Joxer. Usually his Butt Monkey ways are played for laughs, but episodes like "For Him The Bell Tolls" and "A Comedy Of Eros" play his misfortunes in a far more sympathetic light.