After first airing in 2003 on Cartoon Network, Teen Titans quickly became one of the most beloved superhero shows. It followed the exploits of five teenage superheroes: Robin (Scott Menville), Cyborg (Khary Payton), Beast Boy (Greg Cipes), Raven (Tara Strong), and Starfire (Hynden Walch). Together they would save Jump City from a whole host of super criminals and megalomaniacs.
The show won audiences for several reasons, including its multifaceted characters and engaging stories. It was also one of the few kid's shows that could juggle comedy and drama effectively. The emotional episodes were particularly praised for their mature messages and dark themes while never talking down to the audience.
"Nevermore" (S01 Ep06)
During a battle against Dr. Light, Raven takes things too far and nearly kills the criminal. After an incident with breakfast the following day, Beast Boy goes with Cyborg to Raven's room to apologize. Beast Boy picks up a hand mirror, and the two of them are transported through it to Raven's mind, where Raven's rage is causing chaos.
Along with being the first episode to give insight into Raven's past, this episode showcases the importance of friends and family when going through difficult periods of life. Raven's attempts to control her anger involve isolating herself, but only when she receives aid from Beast Boy and Cyborg can she make progress. The B-plot is also good, as Robin tries to keep a nosy Starfire from disturbing Raven, showing that he respects her privacy.
"Masks" (S01 Ep09)
After another failed attempt to capture the elusive Slade, Robin dedicates himself to trying to track him down. Unfortunately, a new criminal named Red X appears on the scene and easily defeats the other four Titans. In a shocking twist, it's revealed Robin is under the mask, hoping to ally with Slade to bring him down from within.
One of the major themes of Teen Titans is the dangers of obsession: several villains in the series become fixated on achieving a certain goal or proving their superiority to the heroes, which leads to their downfall. Here, Robin falls into that trap as he lies to his friends to stop the villain. When it backfires spectacularly, he is forced to work hard to regain their trust.
"How Long is Forever" (S02 Ep01)
Starfire's attempt to celebrate a Tamaranean holiday is ruined when a villain from the future arrives to steal a priceless clock. Starfire chases him into a portal and damages his suit. She then finds herself twenty years in the future, where her friends have drifted apart.
Seeing the Titans drifting apart and becoming depressed and embittered versions of themselves is heartbreaking. Raven, in particular, hits hard, as she has become isolated and insane after losing her friends. It's also capped off by a thought-provoking debate between predeterminism and determinism, which leaves the episode with a much-needed uplifting ending.
"Only Human" (S02 Ep04)
Cyborg finds himself challenged by a robot named Atlas after defeating him in a video game. Unfortunately, Cyborg's cybernetic half limits how much power it can exert, which Atlas takes advantage of to win. He then claims the other Titans as trophies and an incentive for Cyborg to humiliate himself again.
This episode showcases the power of self-doubt. Atlas encourages Cyborg's belief that he cannot surpass his limit and bullies his mechanic, voiced by John DiMaggio, into being his obedient servant. However, he loses his dominance over both of them when they realize their doubt allowed him to win in the first place.
"Betrayal" (S02 Ep10)
Early in season 2, the Titans met Terra, a kind and energetic girl who struggled to control her terrakinetic powers. She developed a romantic relationship with Beast Boy and was eventually brought onto the team as their sixth member when she improved her skills. Unfortunately, this improvement came because Slade recruited her as his new apprentice.
While taking Beast Boy on a date, an army of robots attacks the tower, and Slade confronts Terra and Beast Boy, forcing her to come clean. This betrayal shakes the team to the core, with Beast Boy seeming like he was going to kill Slade during their fight. The animators also enhance the emotional gut punch with fantastic visual storytelling, especially when Terra flees into a hall of mirrors.
"Deception" (S03 Ep01)
To infiltrate the HIVE Academy for teenage super villains, Cyborg employs holographic rings to make himself appear human. Calling himself Stone, he wins the trust of the students and the new headmaster, Brother Blood. However, he also starts to lose himself in the high school experience.
"Deception" drives home how much Cyborg missed out on due to the accident that destroyed his body. During the climax, while fighting against a robot duplicate he left with the team, Cyborg seems to lose control and destroys the robot in a rage. While Cyborg claims it was an act to fool Brother Blood, it can be seen as a visualization of his self-loathing.
"Haunted" (S03 Ep05)
Even though Slade was killed fighting Terra in "Aftershock Part 2", Robin feels like the fight isn't over. One night, after re-capturing the villain Cynderblock, Slade appears and brutally defeats Robin in a fight. However, none of the other Titans see him, which drives Robin deeper into his obsession to stop Slade.
If "Masks" was a look at Robin's obsession, this episode dives into the dangers of unchecked paranoia. The viewers are as helpless as the Titans as Robin's paranoia, brought on by his desire to protect others, threatens to kill him. It's also probably Scott Menville's best voice acting in the show, as he makes Robin sound so angry that he'd be willing to attack his own friends.
"Spellbound" (S03 Ep06)
After being called creepy by Beast Boy, Raven wishes that she could find someone that understands her. She gets her wish when one of her spellbooks is revealed to contain the spirit of an ancient spellcaster, Malchior, and the two become friends. Under Malchior's teachings, Raven improves her magic in the hopes of freeing him from the book.
Raven's struggle mirrors that of many introverts to find someone they can connect with. This episode shows the dangers that this situation can bring: if you throw yourself completely at the first person to connect with you and isolate yourself from your other friends, you risk being taken advantage of. The ending where Beast Boy tells Raven she is not alone is one of the most poignant in the series and hints at a possible relationship between the two.
"Birthmark" (S04 Ep03)
After defeating Dr. Light, Raven locks herself in her room. Beast Boy learns that today is her birthday, and the Titans try to cheer her up with a party. Unfortunately, the celebrations are interrupted by Slade, who has returned from the dead with new powers and a message for Raven.
Season four is considered the best season of Teen Titans, and this episode sets up why. Along with the shocking return of the show's best villain, it also shows Raven at her most vulnerable as she tries to escape the hellish future that she is linked to. It also reinforces the friendship between her and Robin, which would be a major factor in the three-part finale.
"Troq" (S04 Ep06)
The Titans save an alien named Val-Yor and learn about his mission to destroy an evil robot empire. The Titans agree to help, and Val-Yor bonds with them all. That is, except for Starfire, who he despises for being a Tamaranean.
"Troq" offers a harsh but fair entry to racism and bigotry in a way children can understand. Even though Starfire saves his life, Val-Yor never changes his view on Tamaraneans and departs, saying that the Titans are just as bad despite all they did for his mission. This leads to a strong message that it's not your job to change these people: for every Val-Yor, there are a dozen Starfires, and they are who you should focus on.