I’ll go first. Mine is the instant knockout drug. Like Dexter’s intramuscular injection that causes someone to immediately lose consciousness. Or in the movie Split where there’s the aerosol spray in your face that makes you instantly unconscious. Or pretty much any time someone uses chloroform.
Not quite a pet peeve, but close. The whole “We’re not in a (movie/show/game/whatever)!” type of dialogue.
That, or cliffhangers that will never be resolved due to the show/movie either being cancelled, discontinued, whatever. Looking at you, Sliders season 5 ending!
I see Sliders mentioned, I cry.