Whether people acknowledge it or not, often times one of the most engaging parts of a successful television series is a good love story.
Fans sometimes wait years for their favorite 'ship' to finally get together and, when done right, it can be a great success. But then there are other times. Times when a central romance can be one of, if not the biggest, problems a show has.
Just as a series can benefit from a love story, it can be hurt by one. It doesn't seem to matter whether a pairing is tainted by things like egos, abuse, infidelity, or even incest, there have been many times when a group of writers just can't seem to let go of a bad thing, no matter how loud the viewers might be screaming for it to end.