Penny was the leading lady on The Big Bang Theory thanks to her romantic relationship with Leonard and her platonic relationship with Sheldon. However, she didn't need her proximity to the boys in apartment 4A to be important; Penny was chock full of intriguing stories and unique quirks.
Over TBBT's 12 seasons, Penny has done some startling things that fans still can't get over. As the "normal" one in the group, some of her actions didn't make sense to her friends, and they sometimes made Sheldon uncomfortable. However, this is all a part of Penny's charm. It was because of the relatively outlandish things she did and said that gave her character substance.
Her Bullying Past
Penny's bullying past is written in a humorous way but it's actually pretty upsetting considering she was now friends with the very type of people she used to bully. When Leonard confronted his own high school bully, Bernadette and Amy made Penny realize that she was no better than her partner's former tormentor. Penny tried apologizing to those she'd wronged in the past but it didn't end well. As bright and sweet as Penny is, it's twisted that she still used some bullying tactics to get her way (ie making Amy and Bernadette write her college papers).
Stealing Wi-Fi And Food From The Guys For Years
Once again, it's played off as silly that Penny steals Wi-Fi and food from the guys but after a while, it becomes taxing. It's one thing if she was dating Leonard and he offered to pay for her internet and food but that wasn't the case. She continued using Sheldon and Leonard even before they all came close and their relationship was that of friendly neighbors.
It made fans wonder if she would have been as friendly with them if they didn't do those nice things for her. Once again, it's this bullying side of Penny that makes her feel entitled to free things at the expense of others.
Her One Night Of "Passion" With Raj
It was shocking to everyone when Penny and Raj spent the night together. Seeing them wake up naked in Leonard's bed was a vision no TBBT fan thought they'd ever see.
After too much wine, they spent the night together. Penny was so drunk that she didn't remember what happened but Raj remembered it well. After days of thinking that she slept with Raj, Raj admitted that they made out, he prematurely climaxed, and then they fell asleep. Seeing as Raj was one of Leonard's best friends, this was a low blow for both of them.
She Had No Idea She Was Married
It's a known fact that Penny wasn't the smartest person on the show but fans were shocked when she didn't realize that Las Vegas weddings were real. On their way to Howard and Bernadette's house for Thanksgiving dinner, the topic of Las Vegas weddings was brought up and Penny mentioned that she and Zack did one of those for fun.
The entire car let her know that those weddings were real and that she was legally married... Penny has said some outlandish things before but this took the cake.
She Seemed To Be More Interested In Sheldon's Career Than Leonard's
No one can blame Penny for not understanding most of the gang's science jargon. She had no background in science and wasn't even remotely interested in it. When she began dating Leonard, she tried learning more about physics but it never stuck.
Oddly enough, she seemed more interested in Sheldon's work and listened to the problems he was having. Penny's interest in Sheldon's field of study over Leonard's proved that Penny could have taken an effort into Leonard's work but would rather not.
She Hid Her Real Feelings On Having Children
Leonard and Penny talked about their future as parents here and there but it was never concrete conversations. But by the 11th and 12th season, it became clear that being a mother was not on Penny's to-do list. The problem is that she never told Leonard her feelings until it was almost too late. Having children is a huge conversation and the couple should have talked about this early on. By them ignoring the subject, Leonard was heartbroken at the thought of not having kids.
She Spread Bernadette's Pregnancy News
Viewers loved the business-professional side of Penny and Bernadette's friendship. It was great that Bernadette was able to get Penny a job and that Penny was doing so well at it. As colleagues and friends, most of their work talk was confidential. But when Penny told her coworkers that Bernadette was pregnant, all hell broke loose. Bernadette wasn't ready for people to know about her pregnancy and Penny let the cat out of the bag. To make matters worse, Penny lied about not knowing where the lie came from...
The One And Only Haircut
In the eighth season, Penny debuted a new haircut in time for her new job. It was far shorter than her normal hairstyle and threw everyone off. Sheldon, in particular, hated the fact that Penny changed her appearance. Two seasons later, Amy called Penny's hair choice a "brave" decision. Fans (and the characters) had no idea how used to Penny's long hair they were until she chopped it off.
She Tanked Her Interview
Speaking of a new job... When Penny was ready to step away from acting, she interviewed with Bernadette's company to become a pharmaceutical sales rep. Penny didn't know one thing about pharmaceuticals but she was familiar with sales.
Unsurprisingly, Penny did not have a great interview. She has the ability to be a sweet talker when she wants to be but she was unable to be articulate for the interview. The only reason why she got the job was because her new boss found her fear of Bernadette to be relatable.
She Dated Stuart!
It's been proven that Penny could land any man that she wanted and somehow, she was found herself attracted to Stuart. Sure, dating Leonard opened her eyes to dating brilliant men who weren't always a 10/10, but Stuart? He's a total sweetie, but it was such an odd pairing. Alas, the relationship didn't last long because Penny realized she still longed for Leonard. But still, this is one of those things that no one can forget.