Wow, it's almost at 7 pages, and nobody has mentioned the worst commercial currently on American Television?
http://video.google.com/videoplay?docid=788007282255502873
Here it is, for those of you not in the USA.
I used to like Dunkin Donuts until I saw this. Imagine a commercial that could turn away loyal customers
As for past commercials that I hate, the first that comes to mind are the Build a Bear Workshop commercials with the song "Disco Hippie" by Play, playing in the background.
Worst commercial of the 80's: The Mormon commercial where the kid is thinking "I'll tell my mom a lie" and these guys dressed in black, holding flashlights, singing silly song like
"If you tell one lie, it leads to another,
If you tell two lies, they cover for each other,
When you tell three lies: Oh brother!
You're in trouble up to your ears!"
Haha, all while flashlight men dancing around, shining their flashlights. Ha ha ha!