1. The David Seaman Safestyle advert.
I know he was a great goalkeeper and I'm sure he's a nice bloke, but he just looks like a big grinning idiot in the advert, totally charisma free.
2. The Wiltshire Farm Food advert. Employees (presumably) of the company who can't sing, singing "Bring me sunshine", obviously aimed at enticing elderly customers, perhaps the more senile ones.