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.
I used to hate it when people kept wobbling the steering wheel around when driving in a clearly straight road but then Top Gear had an episode featuring some American cars from the 1980s and constantly correcting the steering was necessary because there was so much loose play in the system!
Leaf spring suspension probably doesn’t help either…