Matina Hingis
Italian sneaker and tennis gear maker, Sergio Tacchnini, had provided then #1 ranked Martina a 5-year $5.6 million sponsorship, and required her to wear the shoes and clothes during all tournaments. Well, few years later Martina filed a lawsuit against the company stating that its shoes were defective, unsuitable for tournament play and caused her devastating injuries from wearing Tacchini shoes.

Cybill Shepherd
The Beef Industry Council enlisted Cybill to expound on her beef cravings for the "Real food for real people" campaign, but the whole thing backfired when Cybill admitted that she didn't eat meat.

OJ Simpson
Don't really need to say anything about OJ's double homicide charges causing Hertz to drop him.

Mariah Carey
Apparently Mariah's performance on the Pepsi commercial has jumped over and landed itself on awfulcommercials.com .. yes pun intended.. its the commercial where she's on a motorbike and jumps the pepsi sign.. as of late there seems to be quite a few people who could care less if a celebrity was peddling some product.