The 10 Best 'Big Bang Theory' Running Gags: Knock, Knock, and Knock

The 10 Best 'Big Bang Theory' Running Gags: Knock, Knock, and Knock ...

Most long-running television shows have a fascination with running gimmicks, and showrunners have a habit of keeping them going for the duration of the series'' run. From Friends and How I Met Your Motherto Two and a Half Men and The Big Bang Theory, most long-running sitcoms have a unique twist that makes you feel sensational.

Throughout The Big Bang Theory''s 12-year run, many phrases and character quirks became extremely quotable and recognizable to the show. Without thinking of Sheldon (Jim Parsons) and his most popular phrase for a joke, you couldn''t knock on a door without the urge to do it three times.

Sheldon''''s Food Questions

Sheldon is no stranger to rushing at the prospect of discovering new things. From the way he knocks on a door to how he eats his food, there is always a specific way he needs to do it.

Because he loves doing things in a certain way, meal times usually result in a game of twenty questions with the person bringing it to him. From making sure a vegetable is diced instead of shredded, Sheldon isn''t one to hold back when it comes to making sure his food is exactly the way he likes it.


Sheldon''s use of the word bazinga whenever he made a joke became something fans of the show would use in their own lives.

The phrase never rained beyond the eighth season of the show, with its last mention in the episode titled "The Comic Book Store Regeneration." Nevertheless, Sheldon''s catchphrase remained a long-running gag in the show, and even seven years on remains in the head of every TBBT fan from all over the world.

Sheldon and Sarcasm

Drax the Destroyer in The Guardians of the Galaxy (Dave Bautista) would be the perfect match! It''s unlikely that one of them understands the meaning of sarcasm very well, and it usually goes directly over their heads.

Leonard (Johnny Galecki) often taught him a few key concepts before becoming quite proficient at understanding when someone was using it later in the series. Throughout the series, the authors had a lot of fun with this gag.

Howard and Raj''''s Relationship

Whenever this individual was sharing the screen together, there was bound to be something humorous to follow. During the 12-year run, Howard (Simon Helberg) and Raj (Kunal Nayyar) became friendships on many occasions.

Leonard''s mother, Beverley (Christine Baranski), met them for the first time, and from then on, the show continued to use this to their advantage. From going to couples counseling together to kissing, these couples expanded to become more like a couple as the seasons continued.

Soft Kitty, Warm Kitty

Season one of The Big Bang Theory honed us to these wonderful geeks, but also introduced the Soft Kitty, Warm Kitty song. When Sheldon woke up sick, the guys fled, leaving an unknowing Penny (Kaley Cuoco) to deal with a feverish Sheldon.

This episode was the origin of the Soft Kitty song, and it continued to evolve into one of the most popular running gags on the show. From that point, it became prevalent that, depending on when someone was hurt or sick, one of the gang, usually Penny, Sheldon, or Sheldon''s mother, Mary (Laurie Metcalf) would have to chime in with the song.

Bernadette Sounds Like Howard''''s Mother

Howard''s mother had a voice you could never forget. Whether she was holling at Howard about a phone ringing or phoning to him to answer the door, Mrs. Wolowiz (Carol Ann Susi) was never one for quiet reactions. It soon became apparent that Bernadette (Melissa Rauch) wasn''t either.

The resemblance in Bernie''s mother was uncanny until season 8, episode 18, when she screamed at Leonard and Sheldon during dinner. The similarities slowed.

The Roommate Agreement

A large portion of Leonard''s anger was caused by a contract Sheldon had agreed to before they were born together. Leonard was constantly choking with the roommate agreement as Sheldon would take it to get his way a lot.

Sheldon would refer to this contract in almost every circumstance he encountered. Whether it be a social gathering or something as simple as changing the thermostat temperature in the apartment, it was all covered under the roommate agreement, even the bathroom schedule!

Sheldon''''s Spot

Sheldon emphasized in the pilot episode of The Big Bang Theory that the seat on the couch was his and his alone. So everyone Sheldon learned almost immediately that no one else was allowed to sit there.

It was a huge surprise that when Howard was allowed to sit in his seat, Leonard and Penny had secretly bet on how long he would last. He lasted 94 seconds before declaring that he wanted to switch back. This gag was present throughout the 12 years of TBBT, but it is still a very special part of the show.

Elevator Troubles

The elevator in Leonard, Sheldon, and Penny''s apartment building was out of order until the series'' fourth episode in 2019. The program revealed what happened to the elevator in episode 22 of season 3, depicting an experiment gone wrong, showing that it had been out of service since 2003 before the show had even begun.

When the elevator suddenly dinged, Penny appeared inside the room, which had been completely fixed for twelve years, and it almost seemed like a farewell to this component of the series.

Sheldon''''s Triple Knock

Sheldon''s triple knock was present throughout the show''s entire 12-year run, averaging a few knocks on season one. He was then immediately removed from the show.

Even the rest of the gang would sit on the fun and knock three times, even if Sheldon was ended up. TBBT became such a major component that we couldn''t imagine the show without it. Knock, knock, and knock

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