Richie in The Bear S2 E4 - Forks
Richie is sent by one of the main characters, Carmy, to intern at an upscale restaurant in Chicago in order to get some insight and appreciation for fine dining and hospitality. Richie was initially pretty cynical about the whole experience but inevitably, it helps him find purpose and is a defining moment for the character in the show going forward. It is also a very well received episode in the series.
Shikamaru in Naruto Shippuden - E 82 Team Ten
To be fair, the entire arc is mostly focused on shikamaru, but this episode was a massive stand out. Shikamaru and team ten process the loss of their sensei Asuma. Shikamaru’s father forces him to play a game of shōgi in order to provoke shikamaru’s bottled up grief so that he could clear his mind, and not be stricken by those emotions. This allows him to devise a strategy to defeat the Akatsuki members and avenge his fallen master. It was a very well received episode, and the animation and aesthetic was vastly different from any episode of the series in order to match the tone, and emphasize the emotional depth of the episode.