Exaggerated: Alice and Bob have to be physically restrained from attacking Yoko on sight.
Downplayed: Alice and Bob are initially suspicious and catty towards Zack's new girlfriend.
Justified: Alice and Bob are in a band with Zack, "The Power Trio", and they just scored a record deal, but since he hooked up with a groupie he's stopped turning up to practice sessions, jeopardizing their Big Chance.
Zack's new girlfriend hates his friends, thinking he spends too much time with them and that they're trying to turn him against her.
Alice and Bob hold no particular feelings towards Yoko, and regard her as just another person they know.
Enforced: The writer is an ardent Beatles fan who wants to write a transparent Expy of Yoko Ono.
Lampshaded: "Don't mind my friends, they hate every girl I meet at first"
Invoked: Zack thinks his friends don't appreciate him enough, so pretends to be in a deeply involved relationship with a suspiciously never-seen new girlfriend, hoping they'll realize they take him for granted.
Exploited: Zack is sick of being in a band with Alice and Bob, and is happy to use his new girlfriend as an excuse.
Defied: Alice stops bitching about Yoko with Bob, realising that they're being silly and jealous, and she's probably perfectly nice.
Discussed: "Oh god, you're in a band? Your bandmates are going to hate me, aren't they..."
Conversed: "Alice and Bob are acting like their dad just got remarried..."