Among the best and most memorable episodes of the Avatar franchise, The Last Airbender's "The Tales of Ba Sing Se" is quietly ambitious and genuinely impressive in the depth of character it contains in such a small anthology episode. It was a tremendous success of an episode, and it should have informed a sequel in the next series, The Legend of Korra.
"The Tales of Ba Sing Se" was one of the best episodes of The Last Airbender -- and The Legend of Korra should have done a similar episode set in Republic City.
"Tales of Ba Sing Se" is an episode from Book 2 of Avatar: The Last Airbender. The episode focuses on the various main characters of the series (Aang, Sokka, Katara, Toph, Zuko, Iroh and Momo) as they experience life in the city after so much time traveling. The stories range from comedic (Sokka's tea house haiku battle) to romantic (Zuko's date with a local girl) to even heartbreaking (Iroh honoring the memory of his son on the anniversary of his death).
One of the most beloved episodes of the entire series, the anthology episode is one of the best examples of Avatar's greatest strength: its bench of engaging characters and a setting that brings out the best in them. It's a memorable deep-dive into the personalities of the heroes in various stages of stress or conflict, told in short form for maximum effect. Each character goes through their own journey in the episode, with almost all of them finding peace in some way -- or at least an appreciation for the peace that may escape them. It's a quietly powerful episode with more moving parts than is obvious at first. For many fans of the series, it's a benchmark every other episode can be compared to, and a great chance to see how the characters operate when the stakes are much lower.
The Legend of Korra sets itself up to do such an episode. Most of the series is set in Republic City, the steampunk capital of the United Republic that's full of unique locations and settings. There are warring gangs, the energetic world of Pro-Bending, the metal-bending police force, the business intrigue of Future Industries and their opponents at Cabbage Corp, the spiritual site on Avatar Island... all of these locations provided plenty of potential for any member of the Korra cast, giving fans a chance to see what they're like when they're on their own. Instead, there are only hints at the Pro-Bending life for Bolin, Lin's life on the Police beat and Asami's challenges as a young business mogul.
If these storylines had been given their own episode to shine, they could have been as memorable as the events of "Tales of Ba Sing Se." It could have been the perfect place to expand on characters and define who they were before going into the larger scope of the show's later seasons, especially considering how Season 2's overarching battle against Unalaq, Vaatu and the Dark Spirits didn't leave much room for such things. It also could have provided Republic City with a solid send-off before the cast ventured away to find the new Airbenders in the third season. It could have even been used to expand on the time skip between the third and fourth season, in a city where Korra has left to discover herself.
It would have been a perfect episode to slip into the series, and it's a shame that the show never got the chance to dive into the world as efficiently and organically as "Tales from Ba Sing Se."