Another example is Supernatural. The show was set up as a story about a family and their struggles. I find that romance does distract or take away from this show. It's possible that it could be done if done right, but so far most of the attempts have fallen flat. I wouldn't be adverse to it if done right. Yet, really at the end of the day this story was sold to me as a story about family, in particular about brothers, and that is what I expect to watch.

Really? I can't fathom a romance could work in the least on the show. The very nature of what they do isolates them. How on earth could they juggle fighting demons with a love life? I...can't think of a way that wouldn't come off as incredibly schlocky and wrong for this show. Even with Sarah from S1, who I could see working out with Sam, it would have been too awkward.