Jerry thought he knew one particular thing about Elaine from their dating times of yesteryears. At one admission from Elaine, however–in a conversation with Jerry and George about that “thing”–Jerry realized that all he’d known was jack. “How could a guy not know that?” was Jerry’s unwitting introduction to Elaine’s revelation.
Waiting for the How could _____? from, say, a co-worker is fine, if being pulled onstage at a concert is analogous to how you like your opportunity to brag. If, however, you prefer your own show–the constant touring, the waiting crowds, the “ooo”-“ahh” pyrotechnics–then set the stage by putting up your own rhetorical question: You know why I _____?
The wide-eyed smile on your face when you play the funky muuusic of this line should make your audience fear that you’re about to start dancing too.
From “The Mango”
Episode 1, Season 5
Seinfeld Volume 4, Disc 1
Timecode for the scene: 3:05