It’s from the puffy shirt episode. Jerry agrees to wear a puffy shirt made by Kramer’s friend because she was a low talker and he didn’t understand what she was saying. When he tries the ridiculous shirt on, Kramer tells him he is going to be a pirate and Jerry says “I don’t want to be a pirate!”
Jerry Seinfeld: I don’t wanna be a Pirate, a Cowboy or Switzerland
“I didn’t expect the Spanish Inquisition”
From Seinfeld episode The Face Painter”. “ People. They’re the worst.”
In response to Elaine saying “I will never understand people.”
“I didn’t order assholes with my whiskey”
Raylan Givens - Justified
No one does!
Or “He’s pining for the fjords”
“I always hear “punch me in the face” when you’re speaking, but it’s usually in subtext.”
John to Sherlock in the episode A Scandale in Belgravia.
Computer - “Erase that entire personal log.”
Ben Sisko (Avery Brooks) - Deep Space 9 “In the Pale Moonlight”
Context (rest of quote)
So… I lied. I cheated. I bribed men to cover the crimes of other men. I am an accessory to murder. But the most damning thing of all… I think I can live with it. And if I had to do it all over again - I would. Garak was right about one thing: a guilty conscience is a small price to pay for the safety of the Alpha Quadrant. So I will learn to live with it… Because I can live with it… I can live with it…
Brian
There are a few contenders from the Young Ones too but they are usually dialogs not individual lines. This one might count…
Vyvyan, Vyvyan, Vyvyan. Whenever anything blows up around here everyone always blames Vyvyan. Well don’t blame me, blame whoever rang the doorbell and set off the explosives I rigged up.
Vyvyan Bastard
The Young Ones
Episode: Nasty
Note both this and the blackadder quote above are completely from memory they are ingrained in my consciousness from childhood 
“As with everything else, it’s the thought that counts.”
Sheridan ‘apologizing’ for destroying a Centauri cruiser that attacked Babylon-five.
Too many of my favorites require context. I think even “I hate spunk!” and “As god is my witness…” require knowledge to get it.
So I nominate "A little song, a little dance, a little seltzer down your pants” from MTM, “Chuckles Bites the Dust”. No context needed to be funny.
And to the OP, I remember that line. Never watched the show, but if I ever have call to think of Phoebe Cates, that’s what I think of.
I apologize. The pirate line was from The Puffy Shirt episode of Seinfeld.
‘But she was naked, and all articulate.’ Firefly, Mal’s first encounter with YoSafBrig.
From Doctor Who, A Good Man Goes to War
“Where is my wife?”
From Bojack Horseman, when the woman he’s dating (who recently woke up after being in a coma for something like 20 years) finally realizes that she needs to break up with him.
“When you’re wearing rose-colored lenses, all those red flags just look like flags.”
If that one is too long there is also just ..
I had to, I was drunk
Vyvyan Bastard (in response to why he nailed the front door to the ceiling)
The Young ones
Episode : Oil
Reading these various quotes leads me to realize that most of them can’t be appreciated out of context.
“People like Coldplay and voted for the Nazis. You can’t trust people, Jeremy.” - Super Hans
From Peep Show, Series 3 episode 2. Jeremy & Super Hans are going to buy a pub and are talking about how to set it up, and how people generally like a pub to be. Super Hans is a weird guy and wants to keep the pub junky like they found it, with a washing machine in the middle of the floor. Jeremy says people like nuts & lager at a pub, Super Hans comes back with this line.
The context is meaningless, the line stands on its own. It’s particularly more relevant every day.
The first thing that popped into my head: “I am the one who knocks.”
Yeah thats the tricky bit. Most of the greatest TV lines of all time are actually the greatest dialogs of all time