Does he need it? "Yeah," he replied. "It's like if you're a surfer. You paddle out."
"How do you feel when you're walking on stage in that circumstance?" Mason asked.
"Here goes nothin'!"
This is how he tests and refines his material. "You break down comedy in an architectural way, almost?" asked Mason.
"Yes, I do. Not every comedian does."
"Why do you think you do?"
"I'm an analytical guy," Seinfeld said. "I like science. I like math. I like structure. I like logic.
"I do this joke about, you know, in marriage the most important thing is you've got to listen. A lot of wives complain their husbands don't listen. I've never heard my wife say this. She may have!
"I've never had another joke quite like that joke. It just has it's own structure to it. It's like a magic trick!"
He's 61 now, and has been working comedy clubs since 1975.
"Could you throw everything else away that you've done and you do, and just have standup?" Mason asked.
"Oh yeah. I kind of dream of that," he said. "It's so pure. And I just love it.
"A laugh is such a pure thing. There's no opinion to it. Almost every other creative field has to suffer the interpretive opinion culture, but not a standup comic. You may not like this guy, but if he's getting laughs, he's gonna work."
Seinfeld doesn't need the money. Forbes estimates his net worth at upwards of $800 million, most of it from his TV series, which two decades later his fans still quote back to him.
"They will mostly yell at me things from the show, which I always explain to them, it's not funny to me!" he laughed. "I wrote that for you. There's nothing less funny to a comedian than his own material."
"Is that true, really?"
"Yeah, I'm sick of it. I suffered to come up with that. I'm done with it."
But when the series was done in 1998, its creator admits he was lost: "I didn't know what I was going to do. I was pretty confused at that moment. 'What the hell do you do now?'"
"Because you can't really top it."
"No, impossible. There's only one way to top it. And that's to remain an artist and not a 'star.'"
So he went back into the belly of the beast, even if some nights are rough.
"I don't go, 'Oh, who cares? I got a hit TV series and I've done all -- ' I don't think like that. I think, 'This is horrible.' And I like that."
"What do you like about getting ..."
"It means I'm not an a******," he said. "I haven't become a giant show business a****** -- pardon my language. It's very much what I didn't want to be when I finished my TV series. I don't wanna be that guy.' And I know if I stick to standup, I can't be that guy."
"Because they'll remind you."
"Yeah, they'll remind me in two seconds."
"Have you ever thought you were in danger of going down that path?" asked Mason.