Best 'one-and-done' characters

[Mwnger]

The guy who Ted threatens for bullying Ralph on a shoot.

Yes, Simon Day is amazing in that one. I love his sarcastic "Oh begorrah"

And the end "What did you say?!" "You heard me"

Another fave Simpson one was Surly, one of the Seven Duffs:

Azaria's delivery of "Shut up" is perfect

[Sebastian Cobb]

Also the "oh, I'm not a doctor" guy in that one!

[Autopsy Turvey]

Dick Emery as the (underrehearsed) postman in the Competitions episode of Hancock's Half Hour. "It's against all rules and regulations, hanging fishing rods through government keyholes and things."

[Twilkes]

No idea if he recurred, but Simon Day was an aggressive parent at a book signing in Paul Whitehouse's Happiness - "You're lucky my daughter's here or I'd knock you spark out"

[dr beat]

David Cann's character in Black Books.

'NOW YOU MAY GO!'

[Magnum Valentino]

I've got a definite soft spot for Tony in Father Ted, the one who finally snaps and tells Graham Norton to shut up when trapped in the cave. I completely relate to his end-of-tether-ness.

You really like Tony

I love this place.

[kalowski]

To be really picky, doesn't Tony appear in the caravan in Father Noel Furlong's first appearance? (Ebony and Ivory...)

[Catalogue Trousers]

Tom Baker's captain character.

Also in the whole episode.

The startled passer-by in Life Of Brian ('Ooh! You jammy bastard!').

Edit: Ah, I see that he's already been suggested. Ah well. At least he FITS THE BLUMMEN CRITERIA.

[madhair60]

[QDRPHNC]

The real estate agent in I'm Alan Partridge. He is absolutely brilliant, perfectly captures that rictus-grin politeness of someone who just needs to get through this until the sale is closed.

[The Culture Bunker]

From the Simpsons: Father McGrath from the soap that Marge watches with Lisa when the latter is sick with mumps.

"I thought you were dead!"
"I was!"

Handsome Pete too, maybe, but I have a suspicion he appeared in another episode.

[dr beat]

I've watched Seinfeld a lot over the years and I'm struggling to think of single-scene actors who had a decent bit but were only used once - I guess good storytelling doesn't encourage one-shot characters, and good economics doesn't encourage bringing in an actor just for twenty seconds of footage.

The lady in the homeless shelter was one, not hilarious but held her own against the main characters:

Can't remember now but is the doctor who gives Elaine the rabies shot just in the one scene?

[Twilkes]

Can't remember now but is the doctor who gives Elaine the rabies shot just in the one scene?

I didn't remember him at all but according to the script they went back to him for a single line in a five second scene!

[shoulders]

Can you count Kevin Eldon's kitchen salesman in IAP? He does appear twice in the episode but it doesn't hinge around him.

I thought he was in several episodes? Looking online there a multiple lift interactions.

Love how the banal interactions build and build until Alan finds him unbearable to be around, while simultaneously eating away at Alan is the knowledge Eldon is so jolly and seems permanently content and happy with life in contrast with him.

The reveal of him as a racist at the end, and his impervious reaction to being confronted is as good as it gets.

[Magnum Valentino]

The real estate agent in I'm Alan Partridge. He is absolutely brilliant, perfectly captures that rictus-grin politeness of someone who just needs to get through this until the sale is closed.

As discussed on here recently and worth repeating, the original Blackadder pilot's Baldrick!

[SpiderChrist]

[badaids]

The bloke that plays the racist policeman with sunglasses on in The Young Ones.

The bloke that plays the Think Once, Think Twice, Think don't drive your car on the pavement in The Young Ones.

The bloke that does the You Won't Catch Me With Me Trousers sketch in The Young Ones.

[Oh, Nobody]

Joe Rogan's dad? uncle? in Newsradio "THE TIME FER NEGOTIATIONS IS OVAH"

In the whole episode but fuck it, John Mahoney's jingle writer in Cheers

[Catalogue Trousers]

I'm Alan Partridge again - the South African salesman who negotiates that deal with Alan under a chandelier made of battery-powered torches. Perfect performance balancing menace, disdain and incomprehension.

[Des Wigwam]

Even more Alan Partridge and maybe stretching the definition of a character to its limit but the guy on the intercom just before AP puts his foot on a spiiiiike. Love how the chap realises the tables have turned, how much power he has, and how bored he sounds while also sounding delighted.

Tbh it's the sort of payback situation I long to be in just once in my life.

[Crunk]

The real estate agent in I'm Alan Partridge. He is absolutely brilliant, perfectly captures that rictus-grin politeness of someone who just needs to get through this until the sale is closed.

Pretty sure he's not a real estate agent - I've seen him in loads of other stuff, he must be a full on Equity actor.

*chuckle*

[David Pielingtonburygrot]

Dave Graney in Neighbours

[greencalx]

I know that citing The Day Today is totally cheating, but it is impressive how large a character Spartacus Mills was with just three lines and a sound.

[Captain Crunch]

I love the Jiffy Park guy. 
"We ask that you please bear with us."

[Magnum Valentino]

The bloke that does the You Won't Catch Me With Me Trousers sketch in The Young Ones.

Fuckin right Badaids, my favourite bit out of all 12 episodes.

[dissolute ocelot]

Another Simpsons one is the sarcastic pet shop guy in Duffless: "I want the most intelligent hamster you've got." "This little guy writes mysteries under the name of J. D. McGregor." "How can a hamster write mysteries?" "Well, he gets the ending first, then he writes backward."

Not the only sarcastic shopkeep in The Simpsons, but there's a lot of world-weariness at the futility of hamster moms eating their babies.

[Twilkes]

I love the Jiffy Park guy. 
"We ask that you please bear with us."

I was going to nominate that guy but he appears in more than one scene.

"That's what I'd like to know about it."

[confettiinmyhair]

Brad 'Luke' Pitt in the series 3 finale of Dave.

[ajsmith2]

I thought he was in several episodes? Looking online there a multiple lift interactions.

He's just in one episode, the series one finale. The lift interactions are all in the same episode, not staggered across the series.

I love the weakness of 'it's like cars, this!' as small talk. It's so realistically poor I'm surprised it made the cut in that pre cringe comedy becoming it's own genre era. Like it's exactly what a real person would actually say when they were struggling to make small talk, and not a 'written' awks line.

[shoulders]

Dumbfounded, I remembered him as being a repeating feature of the series