It's not a person, but what about Carousel? Other than that being where the main characters meet, and the basic metaphor of the cycle of abuse, what significance does it even have in the show? I wouldn't even say it's the best metaphor they could have come up with...
Same thing goes with Chitty Chitty Bang Bang - the show is more about the people than the car (well, it SHOULD be at any rate).
Damn Yankees -- the team in the show is the Senators. The hatred of the Yankees causes Joe to make his deal, but that's where their significance pretty much ends.
Hi, Shirley Temple Pudding.