It is really unsurprising that Scarlet Witch and Iron Man had hard feelings about each other. Although the two always stayed neutral while fighting together as Avengers, they shared a lot of common traits. Wanda’s connection with Tony goes way back before Jon Favreau’s Iron Man. WandaVision shows how her parents died in Sokovia in 1999, because of a Stark Industry bomb. This made Wanda and her brother Pietro join Ultron against the Avengers.
Wanda plays with Tony’s mind as an act of revenge during their first encounter in the Ultron movie. She amplifies Tony’s deep-rooted fears about All Avengers dying. With this sense of uneasiness, he created Ultron with the help of Bruce Banner. Tony did not ask for his teammates consent before proceeding. His plan backfires when the AI of Ultron goes corrupt and turns against humans. This, perhaps, was Tony’s most grievous mistake.
The bonding between Tony and Wanda never progressed much, even after becoming teammates. The MCU never tried to fix the bitterness between them, as they had little to no interactions after Captain America: Civil War. Despite the rough edges, Tony and Wanda have a lot more in common than one might think.
The time-gap between the debuts of Iron Man and Scarlet Witch is huge, but they both started off in the same manner. Tony Stark was the precious heir to the Stark family and Stark industries. Tony’s personality before the Afghanistan arc was that of a cocky and careless man. He promoted Stark Industries despite its contribution to war through their weapons division. It was only after Tony’s surprising survival; he became humbled and considerate of his priorities. It ultimately ended up in the making of Iron Man.
Wanda debuted in the MCU In Avengers: Age of Ultron. She and her brother Pietro joined HYDRA’s project, revealing her innate powers. Wanda hated Tony Stark because his weapons caused her to lose her parents. Pietro and Wanda join forces with Ultron in order to destroy the Avengers. However, Wanda soon realized the corrupt motives of Ultron and left his side to become a part of the Avengers.
Unfortunately, the inability to master the given powers led Tony and Wanda to make poor decisions at first. Iron Man and Scarlet Witch have powerful abilities in their own right; however, they did not control these abilities from the start. Tony’s wealth and privilege were no less than a superpower. He misused them for creating destructive mega-weapons. Tony had hardly any sympathy for those born less privileged than him. Although he did not intend to destroy anything with his creations, his failure to monitor their use caused irreparable harm to other people, including the Maximoff family.
Wanda could execute magical powers from the beginning, but she did not know their extent. She officially became a member of the Avengers after Age of Ultron. Wanda never received mature guidance from other heroes about wielding her magic properly. This was not because she did not try. Captain America and Black Widow groomed the new Avengers in Captain America: Civil War, as they were going on missions as a team.
Wanda received tips for fighting strategies, but no one had been able to adequately teach her magic since no one had the same powers as she does. Although Wanda is one of the strongest heroes, not being able to truly understand the powers made her commit mistakes. The incident in Lagos and the creation of the hex in Westview are proof of that.
The death of their parents was the most crucial factor in Tony and Wanda’s lives. HYDRA killed Howard and Maria Stark through Bucky, in 1991. Bucky was just a brainwashed pawn under HYDRA’s control. In Civil War, Tony swore to kill Bucky, despite Steve (Captain America) explaining to Tony the actual situation. Tony regretted his father’s death the most, because he did not have a good relationship with him during his teenage years. The fact that he never got a chance to say goodbye to his father, haunted him deeply.
Interestingly, Tony is the villain in Wanda’s story. Tony was a very indirect factor responsible for Wanda’s parents’ death. The Stark Industries bomb blew off their Sokovian apartment during a random night, as told in Age of Ultron, and it killed their parents. Pietro and Wanda were waiting for another explosion that would kill her and her brother also. That explosion never occurred, and the twins had to live with the grief of an overwhelming loss.
It’s true that Tony made those weapons, but he didn’t intend for them to be used for murder. It’s regrettable that Wanda’s hate for Tony was never fully resolved because the MCU never gave it a chance before Tony’s death in the Endgame.
After emerging quietly in the Marvel Cinematic Universe background for several years, WandaVision finally brought the love affair between Wanda and Vision to the forefront. They bonded because of their connection to the time stone. Their fully bloomed relationship tragically ended with Vision’s death in Avengers: Infinity War. Interestingly, Vision had a striking connection with Iron Man as well.
Iron Man’s original ‘Just A Rather Very Intelligent System‘, J.A.R.V.I.S, got a physical body and the mind stone and became vision. Vision had almost no personal interaction with Tony, the very person who created him. It’s unknown whether they knew about each other’s fates after Thanos’ attack in Infinity War. As Tony‘s closest companion before he had a body, Vision was as important to him as his relationship with Wanda.