Plunging headlong with Elaine into the classic “real or fake?” debate about a certain female body part, Jerry thought he’d ended the discussion with the upper hand. Elaine one-upped Jerry by telling him, in this indirect but illustrative way, to get real.
The analogy takes a monochromatic put-down (“You are so shallow”) and colorizes it with sarcastic flair. Substitute “shallowest” and the “pool” part with any number of similar put-downs that give rise to suitable analogies (e.g., “Just when I think you’re the loudest person I’ve ever met, you manage to stack a few more speakers on the stage”).
Just be sure to properly fit your put-down into the shallow/pool construction, or the analogy for your situation will be the classic throwing yourself from a stage and into the pool of a crowd—who promptly sidestep as you face-plant onto the floor.
From “The Implant”
Episode 19, Season 4
Seinfeld Volume 3, Disc 4
Timecode for the scene: 6:00