Seinfeld recounted, "There was one where a guy had a stroke and we were feeding him on the couch," he said, adding, "I felt very uncomfortable with that episode." If by uncomfortable, he means hilariously dark and funny, then probably many would agree. (On the other hand, stealing a nice old lady's marble rye and being "master of your domain," not to mention making out during "Schindler's List" -- these are apparently fine in Jerry's book.)
The episode Seinfeld mentions is from Season 3 and is called "The Alternate Side." It contains some classic Seinfeldian traits. Kramer is working on a Woody Allen movie and has a line that became a catchphrase: "These pretzels are making me thirsty!"
Seinfeld's car is stolen. And Elaine is about to break up with her 66-year-old boyfriend when he has a stroke. Elaine and Jerry attempt to feed him cookies, and Elaine admits she's worried that breaking up with a stroke victim boyfriend will leave her "ostracized from the community."
The plot lines converge when George's job reparking cars to the alternate side of the street (a quirky New York City street-cleaning regulation) results in Woody Allen canceling his movie and an ambulance unable to get the stroke victim. Funny, right?
In fact, no subject matter seemed too taboo to be touched on in the "show about nothing." As one TV critic noted about the episode's use of a stroke victim for humor: "That's what made 'Seinfeld' so great; it touched on topics that other sitcoms of its era never even dared to touch."
A review from IMDB calls the episode "borderline genius" and adds that it "continues the series' tradition of bringing out the best (read: worst) in the personalities of Kramer, George and Elaine."