There's been some great comedy on both sides of the pond, but personally, I don't rate "Are you being served" (which, as you rightly point out, seemed to go on for an eternity(10 series 69 episodes Wikipaedia tells me)) amongst it, nor IMO "The Office".
Some years ago the BBC did a complete run of Sergeant Bilko, The Phil Silvers Show, and I wish they would do it again: I've got a "best of", but the trouble with "best of's", is that they are not necessarily your personal best: It didn't include the one where they make a Renault Dauphin out of jeep parts.
I did buy a complete set on DVD's, which I found on a US site by googling, but when they turned up, they were bad transcriptions from the Comedy Channel, complete with commercial breaks,some unwatchable, presumably transcribed from old VHS's. Fortunately they were cheap, but what a rip off!
I know I'm getting old, but I love watching Dad's Army: I don't know whether anybody ever tried that on America, the meaning might well be a little obscure.