Don't jump the shark! The key to this show is the ongoing relationship / friendship between Leonard and Penny. Without that relationship the relationship between Sheldon and Penny would not continue. The Ã¢â‚¬Å“Spaghetti CatalystÃ¢â‚¬Â episode was brilliant in exploring how things can work successfully. In that episode Leonard and Penny are like a separated/divorced couple working out sharing time with their Ã¢â‚¬Å“sonÃ¢â‚¬Â Sheldon. The added twist is that Leonard is the practical Ã¢â‚¬Å“motherÃ¢â‚¬Â and Penny the loving but really unknowing Ã¢â‚¬Å“fatherÃ¢â‚¬Â. That Ã¢â‚¬Å“normalcyÃ¢â‚¬Â has to be the center of the show. Nobody would put up with Sheldon if not for Leonard mostly because Sheldon would not put up with Howard, Rag or Penny, if not for Leonard. While the Penny & Sheldon relationship is the best fodder for jokes and witty dialogue it works best with Leonard in the middleÃ¢â‚¬Â¦..Ã¢â‚¬Âhere we goÃ¢â‚¬Â Marginalizing or eliminating the Leonard / Penny relationship will end up resulting in what happened to Happy Days when the Ron Howard Ã¢â‚¬Å“RichieÃ¢â‚¬Â character left and they centered the show on Fonzie. The show just did not work without the focus running through a relatable Ã¢â‚¬Å“everymanÃ¢â‚¬Â character. In the Ã¢â‚¬Å“Big Bang TheoryÃ¢â‚¬Â that Ã¢â‚¬Å“everymanÃ¢â‚¬Â is Leonard he is the most normal and relatable character and the one who bridges the Ã¢â‚¬Å“emotionalÃ¢â‚¬Â Penny to the Ã¢â‚¬Å“rationalÃ¢â‚¬Â Sheldon. Leonard is the little bit of nerd in all of us and the Ã¢â‚¬Å“good guyÃ¢â‚¬Â who brings out the nurturer in Penny. Without Leonard and that bridge, Penny has no need for Sheldon and Sheldon would have no use for her unless nobody else is around. Episode after episode of contriving ways that Sheldon would need to ask for PennyÃ¢â‚¬â„¢s help would really get tiresome. If not for Leonard there would be little or no reason for Penny to be hanging out in Leonard and SheldonÃ¢â‚¬â„¢s apartment as she is not Ã¢â‚¬Å“one of the guysÃ¢â‚¬Â and never should be. The strength of her character is to be the Ã¢â‚¬Å“outsiderÃ¢â‚¬Â looking in Ã¢â‚¬â€œ She is the world that Howard and Raj want to be part of and that Sheldon wants no part of.