As one of the leading characters of the Marvel Cinematic Universe's first three phases, Tony Stark has gone up against plenty of villains. Whether they were looking to conquer the Earth, wipe out the Avengers, or take revenge on him specifically, there are plenty of people who tried to hurt or kill Tony to achieve their own goals.

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No Marvel character ever hurt Tony as much as he did himself. Throughout his time in the MCU films, Tony showed a tendency to self-sabotage and put himself in unsustainable situations. Whether directly or indirectly, he often caused the majority of the problems he faced.

10 Challenging The Mandarin On Live TV

Tony Stark Iron Man challenges the Mandarin to a fight in Iron Man 3

Iron Man 3 followed Tony Stark as he dealt with a string of terrorist attacks across the United States, carried out by AIM under the guise of the Mandarin. After one attack nearly killed Happy, Tony issued a threat to the Mandarin in front of news camera. Tony invited him to fight and gave the Mandarin his address.

Following that, Tony returned home, but didn't immediately prepare for retaliation. The end result of this was the Mandarin destroying Tony's home with a gunship attack, coming very close to killing both Tony and Pepper Potts. Tony spends much of Iron Man 3 low on resources and on the back foot, and much of it comes from his decision early in the film.

9 His Downward Spiral In Iron Man 2

Tony Stark sitting in a giant donut while wearing his armor after his party in Iron Man 2.

In Iron Man 2, Tony began to suffer palladium poisoning as a result of his arc reactor, which was slowly killing him at the cost of keeping shrapnel from his heart. Due to his closed-off nature, he couldn't bring himself to tell anyone about this. Instead, he indulged in binge-drinking alcohol and reckless behavior.

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This results in Tony not only getting hurt, but also angering those close to him and leaving him entirely isolated. Tony's behavior in Iron Man 2 is so self-destructive that much of his storyline consists of Nick Fury and Phil Coulson helping him. They force him to sit down, do something productive, and start to claw himself out of his own emotional hole.

8 Refusing To Listen To Captain America At The Airport

Tony Stark Iron Man calls Spider-Man to restrain Captain America in Civil War.

Throughout Captain America: Civil War, it was shown that both Tony Stark and Steve Rogers spent their time doing what they thought was the right thing. Steve wanted to curtail the threat presented by Zemo, regardless of the legality. Tony wanted to do everything possible to compromise and keep the Avengers as a viable team.

The crux moment for Steve and Tony came in their confrontation at the airport in Germany. Steve made an honest but poorly-explained appeal to Tony that there was more going on. Tony was more preoccupied with bringing in Bucky Barnes and stopping Steve from making things worse. As such, Tony chose to initiate a fight and Civil War's final act was able to happen.

7 Treating Spider-Man Coldly During Homecoming

Tony Stark Iron Man scolds Peter Parker in Spider-Man: Homecoming

One of the more prominent threads throughout Spider-Man: Homecoming was the mentor-student relationship between Tony and his new protégé, Peter Parker. After recruiting him to help in Germany, Tony proceeded to treat Peter coldly throughout Homecoming, only paying him the slightest bit of attention.

Although Tony did learn to be a more responsible mentor and parental figure by the end of Homecoming, his behavior throughout much of the film caused a lot of problems. Due to Tony keeping Peter at arm's length, several people's lives were put in danger throughout the film, and Peter had to fight the Vulture alone to protect Stark technology.

6 His Life As An Arms Dealer

Tony Stark demonstrating the Jericho missile in the first Iron Man movie

Prior to his transformative experiences in Iron Man, Tony Stark was a billionaire arms dealer who sold weapons to the United States military. Although Tony enjoyed a privileged playboy lifestyle as a result, the films show that he suffered on many levels during this time.

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For one thing, Tony was almost incapable of doing anything by himself in either Iron Man or Iron Man 2, relying on Pepper for the business side of things and to manage his personal life. In addition, Tony created a number of enemies in that time, including Aldrich Killian. Finally, Tony was his own worst enemy when he created the weapon that nearly ended his own life in the opening minutes of Iron Man.

5 Refusing To Forgive Captain America

Tony Stark reading Steve's letter to him in Captain America: Civil War movie

Despite often clashing and disagreeing with one another, Tony and Steve Rogers had one of the most important relationships in the Avengers. They came to rely on each other for support, developed something of a friendship, and ultimately rubbed off on each other.

Steve and Tony's relationship came to a near-end in Civil War, following the revelations of Tony's parents' deaths. For seven years, Tony wasn't able to forgive Steve, despite the offer of open reconciliation. As a result, the Avengers remained fractured through to Avengers: Infinity War, and Tony suffered a great deal of emotional pain.

4 Being Unable To Retire

Iron Man attacking a HYDRA base after his ostensible retirement in Avengers: Age of Ultron

One of the biggest contrasts between films came between Iron Man 3 and Avengers: Age of Ultron. In Iron Man 3, Tony blew up his Iron Man suits and declared that he could leave the superhero life. In Avengers: Age of Ultron, he was once again a fully-fighting member of the Avengers with an entire Iron Legion.

Rather than being a continuity error, however, this was woven into Tony's character. As revealed in Civil War, Tony found himself unable to retire, despite his best intentions. The resulting backtrack on his decisions caused a rift between him and Pepper, as well as leading to some of Tony's worse decisions in Age of Ultron.

3 Taking The Fight To Thanos On Titan

Doctor Strange and Iron Man arguing about going to Titan in Avengers: Infinity War

Much of Tony's character arc in the MCU involved his fear of another alien invasion of Earth after The Avengers. As such, when aliens came to Earth in Avengers: Infinity War, Tony is quick to take the fight away from the planet after one brief skirmish. However, he chooses to pick a fight with Thanos, aided only by Peter Parker and Doctor Strange.

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Although Tony may have been unable to take the ship back to Earth anyway, he didn't even try. Even with the help of the Guardians of the Galaxy, the group proved completely incapable of taking Thanos in a fight. The decision saw Thanos gain the Time Stone and an inevitable victory.

2 Creating Ultron And Nearly Ending The World

Tony Stark and Bruce Banner creating Ultron in Avengers: Age of Ultron

Throughout the MCU, Tony Stark created plenty of foes. One of his biggest foes was Ultron. An AI made to protect the world from alien threats, Ultron activated prematurely and decided that humanity was the biggest threat to the world. As such, the AI sought to wipe the planet clean of life.

Tony's negligence in creating Ultron and not telling his team nearly resulted in an extinction event. In-universe, this decision was also treated as his worst. A number of other characters threw this failure in Tony's face throughout the films.

1 Trying To Murder Bucky In Front Of Steve

Tony Stark learns the truth about Bucky killing his parents in Captain America: Civil War

After the explosive but somewhat low-stakes clash at the film's center, Captain America: Civil War ended with a much more personal, intimate battle between its three central characters. After Tony learned of Bucky's role in his parents' death and knowing that Steve kept it a secret, Tony attacked Bucky.

Tony wasn't likely to act rationally after learning such news, but his choice to try to kill Bucky in front of Steve was the worst decision he could have made. It saw Steve step in and overpower him, and was exactly what Zemo wanted him to do. Ultimately, this action was the final nail in what he'd been trying to avert all film: the Avengers falling apart.

NEXT: MCU: 10 Ways Tony Stark Could Have Survived Avengers Endgame