Final answer:
Jerry and George's first and last conversation on the show 'Seinfeld' revolves around the placement of a shirt's second button, showcasing the series' focus on everyday minutiae and circularity.
Step-by-step explanation:
The topic of the first and last conversation that Jerry and George have on the show Seinfeld is the placement of a shirt's second button. This seemingly trivial subject bookends the series, highlighting the show's focus on everyday minutiae. The conversation takes place in the series finale, mirroring their discussion from the pilot episode, reinforcing the show's theme of circularity and the notion that life is a series of similar, inconsequential events.