Things that exist only because humans beings are stupid:
Anti-vaxxers
Flat-Earthers
Warning labels on packages of peanuts telling you that it contains peanuts
And of course, if somebody who was allergic did happen to eat the peanuts, they can totally sue if there was no warning only because it didn't tell them *not* to eat them.
Warning labels telling you not to stop dangerous equipment with your genitals like WTH?
Apparently when Febreeze first came out, it had no scent. The whole point of it was to neutralize bad odors instead of covering them up with a supposedly pleasant scent. But people are so used of the stink of their homes that they couldn't tell if the smells were gone or not. So they added different scents so the product would sell. Of course, most of them smell even worse than whatever household odors are perfuming the air.
Car commercials that show a person driving normally on a normal street, and the warning STILL says: professional driver on closed course, do not attempt.
"Ask your doctor" ads, where they list about 50 scary and horrible sounding side-effects, most of them sounding worse than whatever ailment they're supposed to treat. I once even saw an ad for people with eye irritation from allergies where one of the possible side effects was glaucoma or cataracts. Seriously??
Anti-vaxxers thinking diseases are harmless because their common names are funny, like mumps and measles and chicken pox. I had pink eye one time. The color pink is supposed to be cute and feminine, but there's nothing cute about have inflamed, itchy bloodshot eyes full of gunk that glue your eyelashes together.
Reality TV.
Quack doctor alternative "medicine". Essential oils, arrrrgh!!
People trying to transform their naturally carnivorous pets into vegans.
And when I was younger I used see toy commercials like Barbie, where she's shown moving in stop-motion animation at the start of the commercial, and then it would tell her she doesn't walk or move on her own.
And then there was that ad for the game Guess Who, where they showed the characters on the cards talking, and then it says at the end, "Game cards do not actually talk". (if they did, you probably needed professional help)
Of course, if you're one of the few humans who are not stupid (like most people on WP), then your intelligence has just been completely insulted by such things.