I like the episode "Tongue and Cheek" mostly because it had one of the rangers (Dustin) use his ranger powers to actually fight real crime. Sure, he may have let the fame go to his head a little. Still, it was nice to see a power ranger act like a, well normal superhero for a change. I still don't get why everyone else tried to chew him out.
Hunter and Blake's relationship with Sensei Watanabe isn't very apparent but does undergo a huge change. At the start they were driven solely to kill him on the belief he killed their parents. After being accepted onto the team, Watanabe gives them the same teachings and wisdom he did his original students. By halfway through the season they are following his guidance and referring to him as "Sensei" like he'd always been their mentor.
Cam saving Marah and Kapri... because they're family. Cam has a grudging but really open definition of "family," considering that he's only related to the girls through his uncle Lothor, Lothor is only related to the girls through marriage, and Sensei claims that Lothor's banishment means that he's no longer their relative anyway. But it touches Marah and Kapri right to the heart, they proudly call Cam "cousin" every chance they get next season, and given the choice between going back to Lothor and risking his wrath by helping Cam and the Rangers, they choose Cam.