Throughout its nine-season run, Seinfelddelivered more than its fair share of classic episodes. (Think “The Contest” or “The Puffy Shirt.”) But out of the 172 episodes that the hit NBC sitcom produced, there is one that has arguably penetrated pop-culture more than any other: “The Soup Nazi.” Even writer Spike Feresten is surprised that he’s still talking about “The Soup Nazi,” which aired 30 years ago this week, on November 2, 1995.