Remember when Moonlighting was on - with Cybil Shepherd and Bruce Willis? Remember all that tension - until they finally got together - then the show went downhill!!
Sometimes that happens! But sometimes those relationship changes are successful.
In the show Chuck, Chuck and Sara did progress, and the show stayed exciting.
In Fringe - Olivia and Peter managed to get together and it was a good thing.
X-Files - we waited and waited and it never really happened - it was just implied - and that was a bit of a let down.
What are some that you can think of?