I don't mean like scams or anything like that. I mean what's the ad that has done the worst job as an advertisement? Instead of making you want to buy the product you wanted to avoid it.
A few years ago, Skittles had this ad with a dancing elf looking dude. I used to love Skittles, dentist will back that up, but i just couldn't support that kinda nonsense.
#2 would be those Quiznos ads... I wouldn't eat there anyway, but the deep-fried hamster looking thing isn't going to convince me.
The Quiznos ad was a reference to a popular Flash video from back then. It made sense if you were online a lot, but I can only imagine how off-putting it was without proper context.