Wolverine is the best at what he does, but that doesn't mean he can't screw up. One of the most popular characters in Marvel history, the Canadian mutant has starred in many classic stories over the years, and while he wins more often than not, he also makes a lot of mistakes. Those mistakes have been known to affect those closest to him- the X-Men.
While he's saved the day for the team on many occasions, Wolverine has also done many things that have hurt his friends, both on missions and just in life in general.
10 Killing Them
Wolverine has killed the X-Men. It's hard to let someone down harder than that. In Mark Millar and Steve McNiven's "Old Man Logan," Mysterio can take control of Wolverine and force him to do the unthinkable. Using his illusion casting powers, he's able to convince Wolverine that the X-Men are their greatest enemies, and he kills them all.
This event changed Wolverine's life forever, sending him down a road of pacifism. It also literally let the X-Men down as they were now all six feet under.
9 Being Partly Responsible For The Existence Of Onslaught
In the mid-'90s X-Men story "Fatal Attractions," Magneto pulled off one of his most brazen attacks against humanity, igniting a massive electromagnetic pulse and crippling the Earth. The X-Men took matters into their own hands and went to take him down by any means necessary. Wolverine almost succeeded, but almost only counts in horseshoes and hand grenades. Magneto tore the adamantium from his bones, causing Professor X to mindwipe the villain.
This even leads to a part of Magneto's personality infecting the professor and becoming the genesis of Onslaught. This one event would have major repercussions for both the X-Men and the Marvel Universe, and it was partly Wolverine's fault. The X-Men were too nice to blame him, but he definitely let them down by not killing Magneto in one shot.
8 Archangel Becoming The Heir Of Apocalypse
Archangel has had a hard time since Apocalypse made him into the Horseman of Death, but he's always been able to fight it, until he joined up with Wolverine's Uncanny X-Force, that is. They went after what they thought was a resurrected Apocalypse in the team's first mission but really was a young clone of the ancient mutant. This event opened up a whole can of worms that resulted in Archangel embracing his dark side and declaring himself the heir of Apocalypse.
This lead to a lot of bad things happening, including the destruction of an entire town. While it was a great batch of stories, it caused many bad things for the X-Men, all of which are Wolverine's fault.
7 Bringing Back X-Force
Speaking of X-Force, Wolverine's stewardship of the team caused a lot of problems with the X-Men. Cyclops and Wolverine brought the team back to take down threats before they could affect mutant-kind, and the team didn't skimp on the bloodletting. At first, it was a secret that he, Cyclops, and the team's members, but once the secret was found out, the team would get disbanded.
Later, Wolverine would take it upon himself to restart the group, again keeping it secret from everyone, a secret that got out when Archangel became heir of Apocalypse. His friends were not happy about being lied to, which hurt his standing in many of their eyes.
6 Killing Daken
Wolverine and his son Daken have an exciting relationship. Daken blamed Wolverine for his mother's death and his terrible childhood, devoting himself to taking revenge on his father. The two men would clash many times, with Daken bringing together his own Brotherhood of Evil Mutants to try and kill his father. This would backfire, as Wolverine would kill his son, a move that broke his heart.
This event would have many repercussions for Wolverine, straining his relationship with many of his friends and changing the way some of them looked at him. It would also serve to drive a wedge between the Avengers and the X-Men when they needed to be united the most, as Wolverine also let down his Avengers teammates because of the action.
5 Being Too Far Away To Help When The Hellfire Club Attacks
X-Men: Schism saw Wolverine and Cyclops come to blows over the direction of the mutant race. The Hellfire Club attacked a team of X-Men, quickly beating them, and then threatened to kill a museum full of humans. At the time, Wolverine was across town drinking and couldn't get there, so Cyclops had one of the teenage mutants that the Hellfire Club didn't beat kill the Club's soldiers.
Wolverine reacted violently to Cyclops using child soldiers, but it would never have happened if he hadn't been at a bar. A young teenage girl killed many people because Wolverine wasn't around, and if that's not letting someone down, then nothing is.
4 Siding With The Avengers During Avengers Vs. X-Men
After Schism, Wolverine started his own school for mutants and threw much shade at Cyclops. When the Phoenix Force headed towards Earth, Wolverine went to the Avengers and told them everything about the Phoenix Force, how Cyclops wanted to use it to re-establish the mutant race, and that Cyclops should not be trusted.
This caused the war between the two teams, and eventually, many mutants at Wolverine's school would defect to Cyclops's side, all of them thinking that Wolverine had betrayed his people. While Wolverine would be proven right, it doesn't change how his friends felt about him before that.
3 All The Killing
This one isn't a particular incident but a whole bunch of them. For a long time, the X-Men were not okay with Wolverine's tendency to kill people. During his early years with the team, his whole schtick was slashing first and asking questions never. This attitude often drove a wedge between him and his teammates.
It seemed like every time he got better at controlling himself. He would slip up and kill some people. While it wasn't always completely his fault, more than anything, it disappointed his teammates that he couldn't stay on the straight and narrow.
2 All The Secrets
Wolverine has lived a very long time, and he's forgotten more than most people remember- often literally because of just how much his mind has been messed with over the years. However, even with all of that, Wolverine keeps a lot of secrets. It's a legacy of his times in the black ops world, but regardless of the reasons, those secrets have often come back to bite him and his friends in the X-Men.
The X-Men are a family, and one is supposed to trust their family. Wolverine's tendency to keep things from his teammates, which he often does out of a misguided attempt to protect them, has often disappointed his fellow X-Men, making it hard for them to trust him.
1 Not Killing Sabretooth
While the X-Men have been let down by Wolverine's penchant for ending lives, one place where they would have looked the other way is with Sabretooth. Sabretooth is one of the most despicable villains the team has ever faced- he doesn't care about mutants or humans; he enjoys killing and abusing people. The team has tried to rehabilitate on multiple occasions, and it usually ends pretty badly, often with betrayal or someone on the verge of death.
After a while, there had to be more than one X-Man who was secretly pretty disappointed that Wolverine never killed Sabretooth. While it would be hard, it wouldn't be impossible- drowning would work- and it would have saved a whole bunch of heartache over the years.