In The Conqueror, four of the Planeteers are fooled by Zarm and choose him over Gaia. Tearjerker and nightmare fuel ensue - until Gaia comes to the kids as a mortal and shows them what Zarm is really like. The scene where they apologize and turn away from Zarm definitely makes up for that, though. Especially that part where Gaia hugs Gi and kisses her forehead.
In the episode The Great Tree Heist, Captain Planet is so badly injured by Greedly that he is unable to be summoned, leading to the Planeteers thinking he's dead. Later, Captain Planet is summoned in time to save the Planeteers from being killed by Greedly. After getting them to safety, Gi and Linka jump out of the Geo-Cruiser and run into his arms. Captain Planet hugs them back, looking like the happiest person alive.
In the episode Missing Linka, Linka spends most of the episode running around by herself. While she's inside a mine, she falls and gets knocked unconscious. She's saved by a mysterious bundled stranger (not for the first time that day either), who runs away after she comes to. It's later discovered that the mystery man is none other than Wheeler. She even kisses him for the first time to thank him.
Wheeler not only talks Gi out of outright killing the guy who shot her friend, but even hugs her as she is crying into his chest.
In one of the episodes that took place in the future, we see MAL gaining a Morality Pet in Dr. Blight's daughter Bitzi, who is by far sweeter and more heroic than her mother to the point that she actively tries to help the present and future Planeteers stop her mom from becoming president. MAL tries to pull a Heroic Sacrifice at one point to save Bitzi and ends up doing a full Heel-Face Turn.