You start to know, on stage, when to get off. There's just this feeling that you develop from years and years of doing it; you just feel that "We're getting-- Everyone's really having a good time... and I think, in another few minutes, this is going to start to get old... 'Good night, everybody!'" And everyone's happy! [...] It's just... proportions. Y'know? I guess it's a function of art and economy: that economy is essential to all good art. And I thought "Let's-- " Even though we had done a lot [of Seinfeld]: nine years, 180 episodes, I thought "We can't do one too many, or it's gonna taint the whole thing."