The last episode
I'd find it hard to pick a favourite out of all of them, but none of them caught me off-guard like the George episode did.
It was incredibly moving and I thought it was just about to end after the funeral. Then The Pub happened! I thought I'd wandered into an episode of the league of Gentlemen. An absolutely priceless scene. From shake hands man to the whistling chap me and my partner couldn't believe what we were seeing.