30 Rock
Sherri Shepherd played Tracy’ Morgans wife, Angie, in the comedy program 30 Rock. She was beloved by fans, but not beloved enough to avoid recasting. Turns out, she wasn't the first in the role. That title goes to Sharon Wilkins, who showed up in just a single episode before she was given the boot. Sorry, Sharon...
That 70's Show
Remember when Jackie's mom wasn't played by a supermodel on this show? Brooke Shields is remembered for her time as the teen queen mother, but Eve Plumb was the original Pamela. Jackie's relationship with her mother was just easier to watch when you have this gorgeous woman doling out motherly advice.