Tony Stark didn't become Iron Man by accident, but through a series of personality traits that helped shape the man he would later become. Right up until the end, Stark exercised these traits on a daily basis, sometimes to his own detriment, and those around him. However, he never lost sight of what was important.
Though he was clearly a divisive and abrasive person, Stark's heroism stemmed from the fact that he was a real human being, with the same fears and apprehensions as anyone else. It was how he dealt with those fears that mattered, and it solidified his legacy as the man who saved half the universe from the unthinkable.
His Alpha Attitude
Tony Stark is an Alpha male in every sense, and he uses it without hesitation. He's a natural leader, even if he rubs his team the wrong way, but his charisma tends to make up for it. On his own, Stark's attitude earns him the envy of men, which is a hard act to follow.
He'd soften this attitude considerably, especially after the Battle of New York City in the first Avengers film, where he became much less confident in himself. This would later lead him to a series of bad decisions that almost cost him everything. However, it's doubtful Stark would have gotten where he was, had it not been for his Alpha personality.
His Sarcasm
Sarcasm is one of Stark's best character traits, and also one of his most valuable tools, as defined by the definitive first Iron Man film. With it, he can disarm tense situations simply by cracking a joke or taking people down a peg or two. He's never short on jokes and jabs, and he can sling them without hesitation, even in the midst of people he's never met before.
In battle, this is an excellent fallback weapon, as he can quickly enrage his opponents, and cause them to make mistakes. Outside of a fight, he tends to gauge people on how they react to his verbal barbs. Those who remain relatively unfazed are usually viewed by Stark as potential threats or competitors.
His Cultural References
Throughout the MCU films, Stark makes one cultural reference after another. These tend to center a lot on pop culture, which means the audience needs to be seasoned in order to keep up. Oftentimes, these cultural references are used to make fun of someone else, allowing him to gauge their reactions.
For instance, in Captain America: Civil War, he refers to Bucky Barnes, aka the Winter Soldier as "Manchurian Candidate," which is a nod to the classic Richard Condon book and 1962 Frank Sinatra film about a Korean War commando brainwashed by the Soviets to act as a sleeper agent on their behalf.
His Conscience
While not a perfect man by any stretch of the imagination, Tony Stark was a man with a strong enough conscience to understand right from wrong. Even in his glory days as a leading weapons manufacturer, Stark believed he was improving the world by achieving peace through superior firepower.
Later, when he turned his attention to defensive technologies, he found himself thinking more like the superhero he decided to be. He was so upset over the fact that his weapons were being sold on the black market that he changed his entire approach to his craft, and helped save Earth as a result.
His Lack Of Patience
Stark isn't big on patience, and that became a real problem for him as the MCU films progressed. He was so used to getting his own way as a prolific billionaire, that he had trouble adjusting to the needs of others. This was demonstrated immediately when he assembled the Avengers for their first mission against Loki.
It later played out in a worse fashion when he and Bruce Banner inadvertently gave birth to the Ultron consciousness. It was Stark's rebelliousness and impatience over the idea that Earth would face an insurmountable threat that caused him to jump the gun, and it ended with Stark guilt-ridden over the ensuing catastrophe.
His Courage
Stark's courage cannot be overstated, even when he was at his most vulnerable. The events of the Battle of New York changed him permanently, but Stark never lost sight of what was right. He fought through his fears, even in the midst of panic attacks and PTSD.
Perhaps his greatest demonstration of courage was when he faced down Thanos, not once, but twice. The first time, he single-handedly took on the Mad Titan and managed to make him bleed. Their rematch ended with Stark gaining control of the Infinity Stones, and snapping Thanos out of existence, at the cost of his own life.
His Intelligence
Stark's most obvious character trait was his vast intelligence, which was a virtual wellspring of ideas and concepts. In of sheer intellect, he arguably exceeded his own father, the late Howard Stark, who co-founded Captain America's Super Soldier formula.
It was his intellect that allowed him to build the first Iron Man prototype out of spare parts, and later refine it multiple times over into one of the strongest weapons in existence. With little more than scotch tape and a prayer, Stark's mind could accomplish feats that would make Elon Musk blush.
His Adaptability
Stark was at his best when he had a full laboratory of materials, and a set of blueprints to work with, but no smart person would dare underestimate his ability to yank victory from the jaws of defeat. It was Stark's intelligence and ability to adapt that helped him escape the Ten Rings terrorist group, and forge a new path forward.
Adaptability was the main feature of his Iron Man suits, as well. Each new version of the suit wiped out the weaknesses of the one prior while installing new modules and weapons that could serve him. Even in battle, Stark was able to adapt to the strongest enemies with quick thinking, and some ingenuity, such as when the Hulk was driven into a mad rage by Wanda Maximoff.
His Daddy Issues
In his earlier years, Stark was primarily defined by his strained relationship with his father Howard. He lost both his parents to the Winter Soldier at an age when he most needed some parental guidance, and that haunted him for years. It wasn't until Iron Man 2 that Stark really learned about how his father felt about him.
He had the chance to reconcile with Howard Stark during Avengers: Endgame, even though Howard didn't realize it. This was a cathartic moment for Stark that put things in perspective and helped seal an old wound that he had been carrying around for years, up to that point.
His Self-Sacrifice
When Thanos snapped half of the universe's inhabitants out of existence, Stark's worst fears were finally realized. His inability to prevent the catastrophe haunted him for years, forcing him to give up, and focus on a life with Pepper Potts, and their young daughter.
However, when the opportunity arose to undo the snap, Stark exercised one of his greatest character traits of all: self-sacrifice. Doctor Strange had told him that only one possible outcome out of millions would end in victory, and Stark took the chance in the final battle against Thanos. He managed to gain control of the Infinity Stones, which he knew he was not strong enough to handle, and snap Thanos and his forces out of existence. He died a hero, having sacrificed his own life, and his own happiness, for the sake of trillions.
