I don't know... I like Sam and Diane as opposed to Sam and Rebecca. And, hey, I'm a Rebecca... so that's saying a lot.
I mean, who wouldn't want to end up with Sam???
I still the final episode of Season Five (Shelley Long's last season). Diane is talking with someone in one of the back rooms about her book (I think). Sam's under the pool table. And Diane rolls the Number 8 ball down and it gets stuck in Sam's mouth... Then, later in the epi.
Diane: Where were you?
Sam: Umm... I was at the dentist's. I had something... uhh... stuck in my teeth.