Near the end of episode 10, "The Bull Identity". Bull saves Yamato from falling from the elevated arena moments after shaking off Ababa's Mind Control in a reenactment of when Yamato saved him the first time they met.
Episode 13 "Hog Wild" was full of nice Li Mie moments, Mie was so nice to him. It was like he was apart of the family.
Mie: Most kids are like that, but you B-Daplayers have a sense of honor and purpose.
Li: We have a sense of honor and purpose? I guess that's true... (Li remembers Yamato and his friends behaving loyal and honorably)
Mie: Every true warrior has honor. That means honesty and respect for your opponent. Like you have Li.
Li: (feeling unsure of himself) Hmm, I don't know. I guess I never really thought about it.
Mie: Oh I would say you have a natural sense of honor.
Li: (nervously) I have that? You really think so?
Shame the episode ended on a tearjerker.
Episode 14, when Yamato showed up with the replacement parts for Terry's Winged Ninja during his match with Li.
Near the end of episode 24 "Twisted Sister Act", when Liena was finally freed from Ababa's spell and reunited with her big brother.
When the real Sigma, the guy Liena had impersonated while under Ababa's Mind Control. Then Cain steps in and defends Liena by offering up his own B-Daman Knight Cavalry as a sacrifice to Sigma. This selfless act causes Sigma to rethink his quest for revenge and leave peacefully.
At the very end of Yamato and Enjyu's match Enjyu spots his father, who he had attacked as a young boy and hadin't seen since. Despite everything, his dad came to see his son at his match!
And the only person who was in on Enjyu's plan? Liena.
After their battle in episode 49, Li is returned to normal without any memory of being possessed by Marda B. Wen doesn't have the heart to tell him exactly what happened, but Li quickly indicates that the memories are coming back.
Li: (looks around at the damage caused by there battle) What happened in here?
Wen: You don't remember any of it?
Li: Wen did I, did we...
Wen: (smiles) Never mind.
In "B-DaStorm" Terry discovers that Enjyu has had all his memories wiped and the only way to restore them is to defeat him with the single fragment of B-Energy given to him by Marda B's good side. Terry is left with a Friend or Idol Decision, In the end he choses to save Enjyu. While Enjyu is initially, unhappy with Terry for apparently wasting his B-Energy. Terry reasoned that he was his friend and it was the morally correct thing to do. Terry's choice pays off in a big way later.