In 2007, The Big Bang Theory released its first season, with 17 episodes. Detailing the lives of Sheldon, Leonard, Raj, Howard, and Penny, fans couldn't get enough of the brilliantly awkward group of friends. Along the way, the show introduced girlfriends, boyfriends, and family members, but fans have a soft spot for season 1's storylines.

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The first season gave viewers insight into the fun dynamic between Penny and a group of geniuses. Leonard's crush on Penny grew with time, Raj couldn't speak to women without alcohol, Sheldon was fired, and Howard fell for a friend of Penny's. But after 13 years, there a bunch of things that fans forgot about season 1.

Raj's Hat

Raj is a man who takes pride in his style and skincare routine. For the amount of money Raj's family has, it's surprising he doesn't wear more clothes from high-end designers. He tends to stick to sweaters, zip-ups, and cargo pants.

But in season 1, he played around with hats, particularly a red baseball cap with the number 42 on it. But after the first season, Raj stopped wearing hats and viewers never saw this one again.

Where's Penny's Kitchen?

Big Bang Theory Penny Apartment in Pilot

In the pilot episode when Penny is moving into her apartment, Sheldon and Leonard stop in their tracks as they watch her unpack.

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The view of Penny's apartment from the hallway usually shows Penny's kitchen in the background or at least the window. But in the pilot, the view of Penny's apartment is completely different. The layout shifted and the only thing behind her is a blank wall.

Sheldon Didn't Always Knock Three Times

Sheldon at Penny's door in The Big Bang Theory

One of Sheldon's biggest quirks in the series is that he knocks three times on a door before allowing himself to enter a room. He does this because as a child, he accidentally walked in on his dad being intimate with a woman that was not his mother.

To save himself from ever experiencing that again, he knocks three times on the door. However, in the episode "The Hamburger Postulate," Sheldon runs across the hall to Penny's apartment when there's a tie hanging around Leonard's doorknob. Instead of  "knock, knock, knock, Penny?" he knocks a bunch of times on her door and waits silently for her to answer.

Did Sheldon Like Penny?

tbbt - sheldon and penny

The series pilot was a unique episode for Sheldon. It's obvious that the writers were still working out Sheldon's kinks and his backstory because there are things he did in the series pilot that he would never do in season 12.

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When Penny is impressed by the whiteboard in Sheldon and Leonard's apartment, Sheldon appears to be flirting with her as he leans on his whiteboard and tries to show off his intelligence to her. As fans know, Sheldon and Penny have a brother-sister relationship in the series. It was never romantic.

Penny Had A Balcony

people on pennys porch - the big bang theory

In "The Middle Earth Paradigm," it's Halloween, and Penny is hosting a costume party for all of her friends. She invites the gang to join the fun but Sheldon, Howard, Raj, and Leonard were completely out of their element. They didn't know how to interact with Penny's attractive group of friends and sat on the couch awkwardly.

In the background, however, there are two people dressed in costumes dancing on Penny's balcony. But wait a minute... Penny has a balcony?! It was never shown again in the series.

Sheldon Allows Penny On His Spot

Penny wants to sleep on Sheldon and Leonard's couch on TBBT

Everyone knows how Sheldon feels about his spot on the couch. To him, it's the perfect spot in the house to sit or lounge because of its proximity to the TV, to others, and to the cross-breeze. Anytime someone sits in his spot, a verbal war occurs. However, in "The Dumpling Paradigm," Sheldon encouraged Penny to lay in his spot.

When Howard is across the hall in Penny's apartment making love with her friend, she spends the night on Sheldon and Leonard's couch. But when she sleeps with her head not facing the door, Sheldon tells her it's a horrible idea because she won't be able to see who walks in during a break-in. So, he's essentially telling her to place her head on his spot!

An Inconsistency With Howard's Family Life

continuity issue with howards parents - the big bang theory

In the first season, the audience is still getting to know the family members and the personal lives of the main characters. But after binging 12 seasons of TBBT, fans knew that this season 1 moment between Howard and Raj was inconsistent with Howard's family life.

Howard's dad left his family when he was just a kid. His mom remained single and created an unhealthy attachment to Howard because of her loneliness. In the episode, "The Grasshopper Experiment," however, Raj is complaining about being set up on a date by his parents. He explained that he'd never talk to her once they were married. And oddly enough, Howard said it worked for his parents, but fans know that it didn't. 

CBS Really Put Leonard & Sheldon's Argument On YouTube

sheldon and leonard on youtube - the big bang theory

In the episode "The Cooper-Hofstadter Polarization," Sheldon and Leonard were gearing up to give a presentation on a paper they wrote together. But when the two begin arguing, Sheldon refuses to teach with Leonard and decides to sit in the audience instead. In the middle of Leonard's lecture, Sheldon stands up and begins bickering with him in an outlandish way.

Howard films the whole thing and puts it online. He later told the two grown men that their fight went viral on YouTube and was called "Physicists Gone Wild." Funny enough, CBS actually did put a video of their fight on YouTube under the same name!

Howard Used To Have Co-Workers

howards lab with sheldon in the big bang theory

Whenever the guys are working at Caltech, they're typically seen alone. If they're not by themselves then a member of the friend group is usually there talking to them. However, in the episode "The Jerusalem Duality," Howard's lab is shown and it looks like he has co-workers! There are two men working silently in the background as Sheldon stopped by to talk to Howard. Who are they? What happened to them?

A Continuation Between Seasons

tbbt - continuation from season one to season two

The Big Bang Theory doesn't always end an episode or a season on a cliff-hanger. But that wasn't the case at the end of the first seasons. In the episode "The Tangerine Factor," Leonard and Penny go on their first official date. It goes well but Penny wants to take things slow since it's new for both of them. Instead of season 2 starting off with a new storyline, it continues where season 1 left off, with Penny and Leonard kissing in the hallway after their date.

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