Marvel's popularity came from its proclivity for creating heroes with feet of clay. These heroes became readers' favorites because they were relatable. They made mistakes, lived lives that weren't the best, and struggled with all kinds of problems. Sometimes, these mistakes have short-term consequences; other times they become definitive in the worst way.
Character and writer missteps have made many Marvel heroes' lives much worse. It's complicated things in unforeseen ways, leading them down roads they definitely wouldn't have chosen for themselves. It's changed the way they look at their lives and how everyone looks at them, making things much worse.
10 Nick Fury's Secret War Caused Him To Lose His Power
S.H.I.E.L.D. Directors have a tough job, but Nick Fury often compounded his own life's difficulties. Fury has made many mistakes, but only one of them cost him everything. He arranged a secret war involving Wolverine, Daredevil, Spider-Man, Captain America, Black Widow, and Luke Cage against the new prime minister of Doom's Latveria.
Picking a fight with Latveria was a huge mistake that only got worse. Keeping it secret was bad, mindwiping his heroic recruits was bad, and not insuring that Prime Minister Lucia Van Bardos was dead was bad. It cost him his power at S.H.I.E.L.D. and forced him into hiding for years.
9 Wolverine Jeopardized The Avengers Unity Squad
Wolverine and Cyclops started X-Force together in secret. Eventually, Cyclops revealed the black ops team's secret and disbanded the group. Wolverine felt their work wasn't done yet and brought together a second group in secret. The team pursued a secret and violent agenda that ended when Wolverine killed his son Akihiro.
Wolverine's X-Force was revealed to the Avengers Unity Squad, a team that was already divided at the time. Wolverine's secret broke the team even further and allowed the Apocalypse Twins to destroy the Earth, forcing the group to go back in time and fix their mistakes. Wolverine lost a lot of the trust he had built up and literally destroyed the world.
8 Bruce Banner's Life Was Destroyed On A Bomb-Testing Course
Bruce Banner's tenure as the Hulk has helped him come to terms with many of his mental issues, but it's impossible to say that it's been good for him. He's been hunted and persecuted, even when he did the right thing. All of that came from Rick Jones making the mistake of stepping into an explosives testing area to play his harmonica.
Banner ran out to save the young man and the explosion opened the Green Door, making him the Hulk. Since then, he's gained immeasurable power that has caused a similar amount of anguish. The Hulk's power has been a curse for him, all because one kid didn't realize the danger he was in.
7 Cable's Life Was Marred By The Mistakes Of His Father
Cable grew up in a terrible future, learning to be a soldier in the war against Apocalypse's far-future despotic reign. This sprang from Cyclops' mistakes in raising his son. Cable was going to have a hard life regardless, but it was made much worse by his father leaving his mother for the resurrected Jean Grey.
Cyclops couldn't stop his son from contracting the techno-organic virus, which was the only reason he had to be sent into the future. Any hope of Cable having a normal life was destroyed by his father's many mistakes. The only ray of sunshine is that Cyclops and Jean got sent into the future to raise him for a short time.
6 Spider-Man's Trust In Iron Man Destroyed His Life
Spider-Man has changed a lot, and many of those changes were double-edged swords. Joining the Avengers was a big deal for him and Iron Man took the younger hero under his wing. Spider-Man trusted Iron Man and this mistake led to him publicly disclosing his identity, which led to his Aunt May's near-fatal assassination by Kingpin.
In order to save her, he went to anyone who might be able to help him, but in the end, he had to trade his marriage to Mephisto in order to save his aunt. Spider-Man's life was completely destroyed by trusting Iron Man. He regained his aunt and secret identity but lost the woman he loved and the life he'd built.
5 Jean Grey Mercy For Xorn Cost Her Life
Many Marvel characters have cheated death, with Jean Grey being its poster child. Jean has been resurrected several times over the years, but her longest death came from a huge mistake she made. When Xorn masqueraded as Magneto and almost destroyed the X-Men, she was instrumental in defeating him, using the Phoenix Force to counter his power and take him down.
However, her mistake sprang from her best impulses. Xorn used his powers to give her a planetary-level stroke, killing her. Grey ascended to the White Hot Room of the Phoenix, saved the future by helping Cyclops let go of his guilt, but also stayed dead when mutantkind needed her most.
4 Working For Mister Sinister Had A Huge Effect On Gambit's Life
Gambit is probably the most overrated member of the X-Men. Remy LeBeau was a member of the New Orleans Thieves Guild before becoming a superhero and wasn't exactly the most heroic person. During this time, he took a job from Mister Sinister and helped the Marauders find the Morlock tunnels.
Working for Mister Sinister led to the Mutant Massacre, leaving a black mark on Gambit's history. Eventually, the team found out, driving a wedge between them. Sinister would later use their prior relationship to manipulate Gambit further down the road as well.
3 Xavier And Magneto Keeping Moira MacTaggert's Secret Cost Them The Quiet Council
Years before he started the X-Men, Charles Xavier met Moira MacTaggert and she opened her mind to him. He saw her many lives and how mutants always lost their battle to survive against humanity and the machines. The two of them decided to do something about it. Recruiting Magneto, they lay the foundations for the mutant nation of Krakoa.
However, Magneto and Xavier decided to keep Moira's mutant powers a secret and helped her fake her death. When the truth was uncovered, the results were catastrophic. The Quiet Council lost their trust in them and Moira became an enemy of Krakoa, which hurt both of them with their people.
2 Cyclops Murdering Xavier Had Far-Reaching Consequences
Cyclops has always been a reliable member of the X-Men, but things got hard for him after M-Day. Eventually, the coming of the Phoenix Force gave him hope to fix mutantkind. This put him into contention with the Avengers, which ended with him, Emma Frost, Namor, Colossus, and Magik gaining the Phoenix Force.
Their stint as the Phoenix Five started well, but absolute power corrupts absolutely. Cyclops became consumed by the power and started becoming the Dark Phoenix. The Avengers brought in Xavier, and Cyclops killed him in psychic combat before going full Dark Phoenix. He regretted this immensely afterward. He was branded a criminal, eventually leading to his death when he tried to stop the Terrigen Mist clouds from destroying mutantkind.
1 The Superhero Registration Act Kicked Off Iron Man's Greatest Folly
Iron Man's darkest period began after he signaled his support for the Superhero Registration Act. He may have won the civil war, but his time as Director of S.H.I.E.L.D. was disastrous because of his many mistakes. He missed the Skrulls infiltrating his organization because he was busy going after his friends and he elevated Norman Osborn to a position of power.
The combination of Skrulls and Osborn doomed Stark's tenure at S.H.I.E.L.D. The Skrulls nearly took over the Earth because of his mistakes and Osborn was chosen to replace him. Stark was bad for his friends, but Osborn was worse and these disasters all sprang from Iron Man's mistakes.