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.
The fat funny character.
The “I can fix them” love interest.
Any situation that could have been resolved with any modicum of healthy communication.
Superheroes that cause more damage to the place they’re trying to “save”.