All of them, every single fucking one. Manipulative marketing bastards. Really, when you consider that watching televion produces the same brainwaves as hypnosis, it's actually frightening to think that we're watching commercials in that state. But these fuckers do whatever it takes to try and pedal their shit. Still, if I were to pick the worst of the worst...
Those State Farm commercials where something happens, the kids sign the song, the agent shows up, then they start singing to get all this random shit they want and don't need. What that commercial makes me want to do is NOT buy State Farm insurance because apparently they think I'm retarded.
Also, I really hate Axe commercials. The worst part, is that Axe is one of the few deoderants/antipersperants that works for me without causing me to break out in an allergic rash, so I have to use it, even though their advertising I actually find offensive.