The Big Bang Theory: Season 3, Episode 22

3 - 22: The Staircase Implementation

Leonard fights with Sheldon over the setting of the thermostat, then storms out of the apartment and visits Penny, who has been listening to the argument. He tells Penny that he should have known about Sheldon from their first meeting, and his exposition to Penny of their early days is presented as a series of flashbacks that occupy most of the episode. The first flashback begins with Sheldon's departing former roommate's dramatic warning to Leonard, and the opinion of Louie/Louise, the