Trust in others is something we all strive for, a person that we can rely on to be there for us when times get rough. The same applies to the world of fiction: be they good or bad, a character will need someone to unburden themselves to. This level of trust creates a sort of safety net which allows people to be truly honest with one another, but it can also leave them vulnerable to a betrayal.
Many of us will have had a friend that we fell out with, and the fracture of that friendship is likely to be something we remember for the rest of our lives. I believe this is a big part of the reason that it makes such compelling viewing. There is a certain disturbing thrill in watching formerly close friends turn into the worst of enemies. Their previous closeness provides them with insight that strangers wouldnt have.
Within television a betrayal can be a personal thing between two characters or a far reaching event that encompasses the entire series. If its done correctly and with the right amount of time invested in the build-up, it can a memorable part of the shows history.
A guy who is in too far to many geeky things then he would care to admit. A film, tv and gaming enthusiast he will maintain that Rocky III is an awesome movie until he draws his final breath. Embarrassing Fact- owns five different versions of Ocarina of Time