The show leans into its geeky roots with a memorable discussion about Superman's flight mechanics and the efficiency of Penny's entertainment system.

The next morning, Penny wakes up and is furious at the massive breach of privacy. She demands her key back and confronts Leonard. Resolution:

When Penny asks for a favor—to sign for a furniture delivery while she is at work—the request triggers a cascade of anxiety in Sheldon. Unable to tolerate the "disorder" occurring just feet from his own meticulously organized living space, Sheldon takes drastic action. He breaks into Penny’s apartment while she is away to clean it.

While Rotten Tomatoes notes that Season 1 can feel like the show is still "figuring out the characters," this episode is credited with successfully grounding the humor in everyday life situations, like needing to vent to a friend.

After moving in together in the pilot, Leonard (Johnny Galecki) and Sheldon (Jim Parsons) are still adjusting to life across the hall from Penny (Kaley Cuoco). Leonard is smitten. Sheldon is... Sheldon.

(originally aired October 1, 2007), the series establishes the core comedic friction between the protagonists' hyper-rational, often socially intrusive behavior and the "normal" world represented by their new neighbor, Penny. Plot Overview