It's no secret that Brooklyn Nine-Nine isn't the most realistic cop show on television. The characters have over-the-top personalities and the cases they work on are usually a bit extreme. As the show's protagonist, Jake Peralta is the biggest offender when it comes to workplace shenanigans.
Since the show is a comedy, it's not surprising that all the duller aspects of police work are played up for laughs. But the amount of offensives Jake has committed makes it difficult for viewers to suspend their disbelief. In a normal work environment, Jake would have been out of a job long ago.
The First Halloween Heist
All of the Halloween Heists were extreme, but the first one was arguably the worst in terms of how much property damage Jake caused by himself. To win, Jake had to spend the whole day deceiving Holt and wreaking havoc throughout the precinct. Jake fell from the ceiling of his office and even set a trash can on fire as a distraction. In reality, Jake should've been fired for just one of these offenses. Not only was it dangerous, but the entire heist was a distraction to everyone who was trying to get their work done.
Every Time He Worked With Doug Judy
Doug Judy is a convicted criminal that started off as Jake's worst enemy. However, Jake eventually warmed up to him, and Doug started considering Jake his best friend. Jake doesn't necessarily assist him in his criminal activity, but he does keep secrets from the department in order to do right by Doug. Hindering an ongoing investigation could get Jake in trouble as a citizen, but as a cop, it should have gotten him terminated.
Breaking The One-Way Mirror
The amount of things Jake breaks around the precinct is constantly overlooked. There should be workers around the Nine-Nine every day to fix the damage that Jake has caused, but everything magically fixes itself up.
When Jake is unsatisfied with the way Amy is conducting her interrogation, he continues to beat on the one-way mirror until the glass shatters. Not only did this get in the way of Amy's questioning, but it's another costly expense for the department.
His Unprofessional Workplace Demeanor
Because Jake is written to be a chaotic character, he lacks a sense of professionalism. The way he acts at the precinct is not how people are expected to behave in a professional work environment, but he's only ever called out on it as a joke. Jake will run around the Nine-Nine, scream at the top of his lungs, and act like a child on a sugar high. He isn't respectful to the people around him who are trying to do their jobs, and no real department would ever consider hiring him.
Unwarranted Arrests
Arresting a citizen is not something to be done on a whim, and cops need sufficient evidence in order to keep their suspect in holding. Jake is more of an "act now, think later" type of person, which gets him into trouble when it comes to making arrests. Jake trusts his gut over his head, and it causes him to act irrationally. When Jake brings in a suspect without any proof that he committed the crime, the entire precinct is forced to spend the weekend working so he doesn't walk free. It seems as though Jake's decision should have resulted in more serious consequences.
The Full Bullpen
Instead of working, Jake decides to attempt the "full bullpen," which consists of him sliding across the floor and seeing how far he can go in only his socks. There are several things wrong with the entire concept, but Jake taking off his shoes and pulling stunts in the middle of an office isn't even the worst part.
Jake gets enough momentum and manages to soar across the floor with all of his friends cheering him on. However, Holt opens the elevator right as Jake is coming towards it, and he crashes into his captain. Thankfully, no one got hurt, but at least a dozen rules must have been broken.
How He Treats The Precinct's Captain
No matter who the current captain is, Jake never treats them like a boss. His relationship with Holt was rocky during Season 1 for this very reason, and he was only kept on the force was because of his outstanding detective skills. After they grow closer, as a running gag Jake slips up and calls Holt "dad" quite often. Although it is touching because Jake doesn't have a good relationship with his real father, it doesn't feel appropriate to refer to his boss in that way.
The Jimmy Jab Games
The Jimmy-Jab games are one of the only times Jake gets into any serious trouble for his actions. When Holt was out, Jake and the rest of the precinct spent the day competing against each other in a series of insane challenges. Not all of them were safe, and it's shocking that more people didn't get hurt over the course of the shift. But Jake completely abandoned work for the entire day and caused even more damage to the building, in the process. Not many cities would put up with a precinct that runs as the Nine-Nine does.
Trash Talking Holt To Jimmy Brogan
Fed up with his boss, Jake goes drinking and begins to trash-talk Holt to his favorite author, Jimmy Brogan. Jimmy intends to write a piece on Holt, and Jake drunkenly agrees to go on the record. When Jake sobers up, he realizes that he made a huge mistake and his actions could ruin Holt's reputation. Jimmy agrees not to write the story, but when he calls Holt a gay slur, Jake punches him in the face. What Jake did was admirable, but from a professional standpoint, there were a lot of things about this situation that wouldn't fly in a normal workplace.
His At-Work Activities
The biggest reason Jack should be fired is that he never actually works while he's at work. He's seen going out in the field, but whenever he's inside the precinct he's chatting with his friends, playing games, or doing other unproductive tasks. While it would be boring if viewers were forced to watch Jake do paperwork every episode, that doesn't take away from the fact that he spends too much time goofing off. No cop at Jake's level would be able to get away with his amount of shenanigans.