I hate any car ad that shows grinning happy morons pretending their shopping-box-on-wheels is a desirable piece of kit. I hated those dancing Citroen Transformers. The Ford Focus advert with the yelling voiceover, I hate that so much that if I ever meet the person responsible I will tie him to the rear bumper of a Focus and pay someone to drive it from John O'Groats to Land's End (since I would only ever drive a Focus myself under extreme duress).
OTOH, I quite like the Honda adverts (impossible dream & everything we do) and some of the Audi adverts are OK. however, I don't drive an Audi or a Honda, and have no great desire to do so).
My favourite car ad of all time is the Fiat Strada "built by robots".