The Scarlet Witch's grief over losing her children put an entire world at stake, but the Vision's reaction nearly destroyed two universes. In contrast, Wanda's breakdown nearly seems reasonable; especially considering how the systems that should have supported her failed her. Vision's larger mental break is often overlooked, but perhaps that's because no one on his Earth remembers it.

After losing her children back in John Byrne and Mike Machlan's run of West Coast Avengers, Scarlet Witch's grief was forcibly repressed and her unaddressed trauma led to her subconsciously attacking the Avengers. Brian Michael Bendis and Olivier Coipel bring things to a breaking point in the event House of M, a powered-up Wanda seeks to recreate her lost family and build a perfect world for them to inhabit. Her world domination ends up being quite brief, but her act of grief ultimately results in the Decimation. Erasing millions of mutant's powers has consequences, and Wanda has been paying for it for years, only recently finding some form of redemption. Throughout all of this, Vision was going through an entire ordeal of dying, being rebuilt, losing his emotional core, and being dead again. However, there was a brief moment where was fully himself and had the opportunity to regain what he and Wanda had lost: their boys.

Related: Vision Gets a Horrifying New Look in Marvel's Dark Ages

In the epic DC/Marvel crossover JLA/Avengers #4, by Kurt Busiek and George Perez, the heroes of the temporarily merged Marvel and DC worlds learn their real histories. As they vow to restore their respective realities, the heroes find themselves under attack from Vision. Refusing to return to a world where his children are dead and Wanda will suffer once more, the syntheziod takes on the combined forces of the Avengers and the Justice League.

 

Vision's breakdown in JLA:Avengers.

In the end, Vision is telepathically brought back in line by Martian Manhunter and talked around by Wanda. Even though any consequences of Vision's attack are averted, the scale of his actions here drastically outsizes Scarlet Witch’s own break from sanity. Wanda chose to create a new reality where her friends could be happy, but Vision fought for a plan of action that would have caused two universes to be destroyed if he'd been successful. What's particularly heartbreaking about this is that no one, including Vision, remembers the events of JLA/Avengers. Scarlet Witch doesn't know what he was willing to do for their family, and the version of Vision that was with Wanda when their children died was cold and soulless.

Had Vision remembered this adventure, he might have been a bit more understanding of Wanda's decline in mental health after losing their boys. Who knows, perhaps he could have prevented the events of House of M by getting Wanda the psychiatric care that she so clearly needed. It's easy to see how that version of Vision would have empathy for Scarlet Witch since he was willing to do even worse than she did when he was in the depths of grief.

More: Why Vision and Scarlet Witch Have Been Sidelined in Marvel Comics