I'm a huge Castle fan and I will fully admit that Becket/Castle is my favorite pairing and the sexual tension between the two just crack me up. However, that can only go on for so long until the fans get bored of it and I have always worried about how the characters would be written afterwards. I've seen far too many couples that once they're together they either don't feel like the characters I've grown to love or they keep running into issues/drama that just feels are only being used because the writers don't have any other ideas.

( Spoilers for season 4 and 5 ahead )