Setup and punchline are the same

The best one I know of which truly conforms to the OP comes from the long-running British radio comedy show I’m Sorry I Haven’t a Clue, in the days when it was hosted by the late Humphrey Lyttleton. A standard joke was him belittling the panellists and the show itself. After one round he enunciated thus: “That went off very well! Let’s move on. Oh, hang on, I read that wrong, let me do that again. That went off. Very well, let’s move on.”.

The definition of bigamy is having one wife too many. Monogamy is the same.

Racist as hell, but it’s the best example I know:

Q: What happens when a Jew with a hard-on walks into a wall?
A: He breaks his nose.

Q: Correct! Now, what happens when an Asian with a hard-on walks into a wall?
A: He breaks his nose.

Why does a chicken?

How long is a Chinese name?

There’s a Robot Chicken episode about Batman and the Joker. The Joker gets a long-overdue death sentence and at his electrocution, Commissioner Gordon reads it out:

Gordon: Maurice P. Joker… for 2,391 counts of murder [sub]and many other crimes that seem minor next to 2,391 counts of murder[/sub] you have been sentenced to death!

Source

I remember a Howie Mandel bit from way back when he still did stand up:
“I was in a restaurant. And when the waiter came, I said “Ewww, the waiter came””

In the movie The Truth about Cats and Dogs, Janeane Garofalo hosts a radio call-in show giving advice about pets. One guy calls in insinuating he wants to have sex with his dog, Janeane replies “It’s OK to love your pets, just don’t LOVE your pets”.

“Innuendo. In YOU end-oh!” I remember it being used in **
Scrubs**.

TCMF-2L

[Moderating]

Can we please not perpetuate jokes that even the teller recognizes as “racist as hell”? What good could possibly come of that?

Humph had a lot of those.

‘The show has just been awarded the UN Funny Award! I’m sorry, I’ll read that again. The show has just been awarded the Unfunny award’.

Of course, it has to be delivered by Humph for maximum impact.

She was so fat, the when she sat around the house, she sat around the house!

A bus station is where a bus stops. A train station is where a train stops. On my desk, I have a work station…

That reminds me of the old George Miller joke about going to a fancy restaurant. “They had a waiter for everything! The water waiter came by and gave us water. The butter waiter came by and gave us butter. Then the head waiter came by…”

From Benny Hill:

What is this thing called love?

One half doesn’t know how, the other half lives!

He also had a bit where there was confusion between a “music album” and a “musical bum”.

There’s a joke like this in pretty much every SNL Celebrity Jeopardy sketch, where Sean Connery misreads one of the category names,

Punch cartoon, 1925:
Doctor: What did you operate on Jones for?
Surgeon: A hundred pounds.
Doctor: No, I mean what had he got?
Doctor: A hundred pounds.

I found a semi-humorous example this morning on another website:
You can’t change the people around you, but you can change the people around you - unknown

Somewhat similar – soimething I came up with:

“The one thing you can say about a Bad Experience is that it’s a Good Experience.”

Ooh, got one…

Rodney Dangerfield on Johnny Carson, 1983.(time stamp to 5:14)

This one girl told me come on over, there’s nobody home.
I went over, there was nobody home!