Finales

Beloved American sitcoms have a bit of a tradition of an iconic grand finale, a la The Mary Tyler Moore Show, Cheers, or The Office for instance. Big, emotional finishes wrapping things up nicely for the audiences that loved them. Meanwhile this scenario is rarer in Britcoms, and I think the main reason being that unlike American shows that adhered to a yearly September-May schedule, many of them - particularly in the first coupla decades of British tv - would air a season and then go away for 2, 3, maybe 4 years like Fawlty Towers, without anybody really knowing whether they were coming back or not. 

The few iconic BBC series finales I can think of:

Only Fools and Horses - yes, the intended finale came in the 1996 trilogy but the public demanded Sullivan bring the show back, and while the "real" finale isn't as good, the final final final scene in which Rodney asks Del Boy if he is anything like the man who turned out to be his real father and Del Boy answered, "Freddie the Frog was a professional burglar. He was disloyal to his friends. He was a womaniser, a home-breaker, a con-man, a thief, a liar, and a cheat... So no Rodney, you're nothing like him.", made it all worthwhile as a finale.

Extras - just fantastic.

Gavin and Stacey - if when Dave coaches saves the day in the end and says goodbye to Baby Neil while leaving doesn't make you verklempt then you're not human.

Blackadder - maybe the best finale ending scene of all time, in a show that had exactly ZERO earnest, non-funny scenes in all the previous episodes.

I think that's pretty much it?