I like "Terror at 20,000 Leagues" because the Frankenbob segments make the plot fit the runtime. It also perfectly puts the 2D characters in the segments. And finally, that ending is the best part of the series.
Gas Station Vacation perfectly mixes torture with dumbness. However, it has one bad quality-the squeeze your faces off joke. I hope TV Tropes po ut that in The Patrick Star Show's Nightmare Fuel page...and as the image. But, it is also really funny.