Philip

Philip is the strongest AND the coolest.

Spot on the Couch
The most notable feature of Sheldon's obsessive-compulsive disorder is his refusal to sit anywhere other than his designated spot on the far left cushion of the couch in his apartment, which he considers his "single point of consistency in an ever-changing world" and "the singular location in space around which revolves my entire universe", exceeding his love for his mother. He describes his spot on the couch as being his point 0, 0, 0, 0 if his life were a Cartesian coordinate plan. Sheldon regularly reproaches Penny and other people for sitting in his spot. Even disruptions to this location are enough to disturb him. Although he did allow Penny to sit in his spot in the first episode, as well as Howard, for a short time in "The Apology Insufficiency", only 94 seconds later, he reclaims his spot. As well as his designated spot in the apartment, if Sheldon is ever in a different area where he is going to sit down, such as Penny's apartment, he has to choose the best sitting location based on such things as optimal television viewing, lighting, airflow, and cushion density. In "The Werewolf Transformation", when his barber was ill and chaos ruled his life, he didn't object to Penny sitting in his spot. In "The Mommy Observation" Leonard reveals that Sheldon has a very sensitive butt and can tell when someone was sitting in his spot.

Quotes
"Bazinga" - He says this whenever he makes a joke.