American counterparts include The Honeymooners and Sanford and Son, but failure comedy hasn't been hugely popular in America, at least not since the days of Charlie Chaplin. Right now, Raising Hope is a sort of half-failure sitcom in that the Chance Family often aspires to wealth but they're never really disappointed when they don't get it. (Blackadder's Stephen Fry said in a TV interview that while American comic protagonists tend to be optimistic "wisecrackers" with "the biggest knob in the room," the central figures in British comedies, including Only Fools and Horses' Del Boy, are "utter failures," or "people who want life to be better and on whom life craps from a terrible height.")

By most measures the most popular sitcom in British history, Only Fools and Horses is a failure comedy. That's not because the show is unfunny but because its regular characters are repeatedly thwarted in their attempts to better themselves. And in contrast to sitcom characters in more comfortable surroundings, their calamities aren't just cute learning experiences (as in this Mary Tyler Moore Show episode) but real financial setbacks.

Welcome to the “100 Best Sitcom Episodes of All Time,” a countdown for 2012. Each episode will get a separate blog post, counting backward toward No. 1. A list of the programs revealed so far is here and an introduction to the project is here .

On Only Fools, the Trotters, a family of junk dealers, are stoic but hardly content to watch opportunities slip through their fingers at the end of most episodes. And because this is a British sitcom, there's always the sting of class snobbery to go along with their low standard of living.

Del Boy: I deserve a bit of the good life, worked hard enough for it, I mean I've always been a trier. Where's it got me? Nowhere, that's where it's got me! We live half a mile up in the sky in this Lego set built by the council. Run a three-wheel van with a bald tire. We drink in wine bars where the only thing's got a vintage is the governor's wife! That's why I want to grab this opportunity with both hands, Rodney. You know, he who dares wins. This time next year we'll be millionaires.

Rodney (Del Boy's brother): Do you honestly believe that Del? I mean, do you really think we can make a success of this?

Del Boy: Of course we can, Rodney. The door will be opened to a new world. It'll be like...like Alex Through the Looking Glass.

As the above quote suggests, Delboy (the leader of the family business, played in both cringeworthy and sympathetic fashion by David Jason) is not the sophisticate he thinks he is. When he does gain entrance to a mansion, his small talk with the lady of the house includes: "This is beautiful, innit? Eh? Bet you've held a few balls in here, m'lady?"

In "A Touch of Glass," the Trotters' assistance to a rich woman with a stalled car leads to another of Delboy's get-rich schemes. He passes himself as an expert in cleaning and repairing cut-crystal chandeliers, hoping that the specialty craft will lead to hobnobbing with wealthy estate owners.

Grandad: The house — is it old?

Lady R: Yes, the original structure was built in 1642.

Grandad: Oh! Still, you've done it out nice!

To the British, "A Touch of Glass" includes a scene as iconic as Lucy in the candy factory, or Sammy Davis Jr. kissing Archie Bunker. I won't spoil it here, but I will note that John Sullivan (who wrote all 64 episodes) started with the last scene and worked backward from there. As indicated elsewhere on this Top 100 list, I admire sitcoms that commit to a story or scene — instead of hedging with B, C, and D stories — and "A Touch of Glass" really hinges on one moment. Only Fools and Horses, like The Honeymooners, has a lot in common with murder mysteries in that you know how it's going to end (the fortune lost, the killer revealed) but don't know how it will get there. But only the best of them, like "A Touch of Glass," hold up to repeated viewings.

• Unfortunately, the complete episode is not on YouTube. But you can cheat and just watch the ending here. The title of the clip partially gives things away, but watch it a second time and note how carefully the scene had to be shot to maintain an element of surprise.