Angst? What Angst?: Sometimes, the Archie gang seems ridiculously sociopathic. When something that should be traumatic, like thinking all your friends are dead or realizing you turned into a monster, happens, the characters response usually doesn't go past annoyance.
Hilarious in Hindsight: Everyone gradually turning into Veronica which spread like a virus. This is ironic if you're a Resident Evil fan, since there is actually a virus called T-Veronica.
Narm Charm: Some of the voice acting can get a little narmy (Veronica being the biggest example), but considering all the homages and references to B-movies, it actually fits quite well.
Squick: A case that could be both in and out of universe. In "Zombies of Love", the doped-on-love potion Archie is suddenly wearing a hat and presents Veronica with a pillow as a gift. When Veronica inquires as what the unusual-feeling stuffing is, Archie removes his hat to reveal he stuffed it with the hair from his head. Veronica freaks out and finally hits her breaking point with the constant attention.
The Woobie: "Something is Haunting Riverdale High" features Dilton remarking that unless his classmates need an invention or mechanical/scientific help, he can go weeks without even being noticed, placing him in this trope.