When Jesse and Becky (who are only dating at this point) have a fight, DJ is worried that she'll lose her (the only mother figure she has). Becky assures her that no matter what happens, they'll always be friends.
Danny and Jesse talking Kimmy out of being a 'teenage bride' made for a great moment.
Jesse helping Michelle teach the class the Greek dance Papouli taught her before he died.
After Steve and DJ go on a game show and realize they don't know as much about each other as they thought, DJ starts questioning their relationship. Then Steve says how it's a good thing that they don't as much about each other as they thought.
Steve: The way I see it, every new thing I learn about you is like opening another present. It makes everyday feel like Christmas.
The entire final scene of the show with DJ and Steve reuniting, and the last quotes.
Joey: (about Michelle losing her memory) But we stuck it out, just like we always have.
Danny: Just like we always will.
(cue group hug and credits)
Steve's return has one that qualifies as both this and a Crowning Moment of Funny, a line that shows that some things never change...