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The Longest Running Jokes In 'The Big Bang Theory'

Voting Rules
Vote up the jokes that make humor an exact science.

The Big Bang Theory is one of the longest-running sitcoms to ever air on TV. It remains a hilarious watch for fans, especially due to the presence of several recognizable tropes that have an evergreen element of comedy. These include catchphrases, recurring appearances and jokes, and mannerisms. Here are the longest-running jokes on The Big Bang Theory.

Photo: CBS / Pinterest

  • 1
    109 VOTES

    Sheldon Knocking Three Times On Doors

    Sheldon Knocking Three Times On Doors
    Photo: CBS / Pinterest

    Sheldon has a compulsive need to knock on doors three times to announce his arrival, as well as utter the name of the person he wants to meet after each knock. During times where the door opens before he says their name, Sheldon freaks out and feels the need to knock again anyway. 

    109 votes
  • 2
    93 VOTES

    Penny Freeloading Off The Guys

    Penny Freeloading Off The Guys
    Photo: CBS / Pinterest

    The first half of the series shows Penny taking advantage of Sheldon and Leonard's willingness to share their things with her. This ranges from her not paying for any of the food and even having Leonard pay for her rent one time. An extension of this gag features Sheldon constantly changing the WiFi password that makes references to Penny's freeloading nature.

    93 votes
  • 3
    71 VOTES

    Sheldon's Love For His Spot

    Sheldon's Love For His Spot
    Photo: CBS / Pinterest

    Sheldon regards a particular spot on the couch to be in a "state of eternal dibs" in his favor. He gets in arguments with anyone that dares sit in his spot, with certain episodes even dedicated entirely to Sheldon freaking out when his spot is compromised.

    71 votes
  • 4
    93 VOTES

    Sheldon's Inability To Understand Sarcasm

    Sheldon's Inability To Understand Sarcasm
    Photo: CBS / Pinterest

    His lack of social skills means Sheldon takes every statement at face value, not realizing when someone's being sarcastic. This reaches the point where he has to ask the person if they're deliberately being sarcastic, and keeping a score of how many times he was able to detect sarcasm.

    93 votes
  • 5
    85 VOTES

    Sheldon Reminding Everyone He's Not Crazy

    Sheldon Reminding Everyone He's Not Crazy
    Photo: CBS / Pinterest

    Sheldon's neurotic personality leads each character that meets him to assume he's crazy, which he's quick to point out isn't the case because his mother specifically had him tested to make sure.

    85 votes
  • 6
    81 VOTES

    The Roommate Agreement

    The Roommate Agreement
    Photo: CBS / Pinterest

    Sheldon constantly brings up the "Roommate Agreement," a set of documents he considers legally binding over his living situation with Leonard. This makes life difficult for Leonard as he has to put up with ridiculous terms as per the agreement. Examples include Leonard agreeing to meet with Sheldon in the past if he creates a time machine, and not being allowed to whistle in the apartment.

    81 votes