Let me try to explain what I mean. What I love about the way it was handled in the shows over all plotline and the reason they are the only couple in TV history I have really cared about. Is that there was a believable build up to it and both characters had to grow and had things to learn before this could work. It was earned so you can care about what happens and unlike in most shows you can see the relationship is about more then sex so it feels much more real and you can care about what happens. Season five is well on it's way to being my favorite season but i don't think I would have bought into the things that are happening now if we hadn't had the story lines we did in seasons 3 and 4. Beckett needed to put her stuff behind her and I would not have bought that she had done it with out the events of seasons 3 and 4. Castle also needed to grow he not only needed to stop being a play boy but back in season 2 he was only coming in to the 12th for Beckett. He needed to evolve into someone who would come in because he was needed even if he didn't have a future with Beckett. That is why 47 Seconds was such an important episode if you ask me. After all that work now I can buy them as a couple and I know that they will not be breaking up over silly things like Caslte's Ex staying with him because they have both invested a lot of time and effort into making this work and they are not just going to give up. This is what happens when you combine great writing with great acting. You get a classic piece of TV.