I hate to say it, but the Sarah McLachlan commercials about the dogs. It makes me feel manipulated and played.
The Colonial Penn Insurance commercials with those boring old women. "Honey, it costs just as much to bury a woman as it does a MAN!".
Flo the Progressive Insurance lady - she should be tied to a pole so birds can peck at her liver. I think I mention her in every commercial snark thread, but they keep getting worse and worse. The first one or two were cute, now they are just obnoxious.
The one for the fried chicken restaurant, with the woman talking all stereotypical about how it is "her" chicken and how good it is...is it Church's or Popeye's? I hate both of their fried chicken anyway - the skin is gross and oily.
The Lexus holiday commercials; I find them blatantly materialistic and snobbish!
Any of the drug commercials that list all of the nasty side effects, including cancer and/or death!