Sam's reaction to learning Claudia is pregnant with Sonny's child.
Sam: I just don't understand why Sonny can't keep it in his pants for like five seconds. He's around someone for five minutes and he impregnates everyone. I don't get it!
Bonus points for hanging the lampshade many viewers feel about how many children Sonny has fathered. For the record, he's had five, three biological, one adopted, one stillborn.
Any scene with the Quartermaines.
AJ's reactions to Alice when she takes someone out.
The Lampshade Hanging which introduces Roger Howarth's Todd Manning expy (later revealed to be the character Franco); he resists responding to requests from a stagehand for a person named "Todd" to retrieve paper towels. This new Todd ends up being a janitor.
Alexis realizing that the father of her eldest child, Sam may have been Julian Jerome of the Jerome crime family, making it the the second(technically the first) time she's had progeny by a member of the underworld.
Alexis: My god, did I have ANOTHER kid with a mobster?!"