I think once you are detoxed, it doesn't make you immune to future toxicity. It seems more like Rick and Morty attempted to avoid future toxins instead of figuring out better coping strategies so the toxins don't stick as deeply. They don't think "This part of me has been temporarily erased, but the generators and reactors of it are still inside of me and shit still happens in life. I better get into mindful meditation yoga or pills or some other crap to function better in life."

Both of them start out more relaxed, unburdened, and level headed. They're honest in discussing their feelings. I think this is where they're at their healthiest. Then they decided how they want to be, informed by a desire to keep feeling bliss and comfort.

Healthy Morty, no longer burdened by his traumas and anxieties, decides to go the way of a coked up d-bag. I believe this is a conscious choice on his part, the means justifying the ends. He doesn't allow himself to be shaken by anything or even to fully process what's happening. He reacts. His reaction are informed by desire for personal gain and his avoidance of perceived toxins, like a new convert to Paleo CrossFit.

Our Morty, assuming we have been watching the same Morty, has experienced a lot of time. A year in his dog's dream as a kept man, a lifetime as a cancerous carpet salesman, frozen time, layered time, committed a ton of murder, been a father.

All of this without dying is what led to S3 Morty. His toxic side consists of all his earliest underlying traits, the sort of Morty you'd see in fanfic. Except his healthy side didn't pull any wisdom from his past experiences, it just went American Psycho.

Meanwhile, Healthy Rick has lost all bite and passion. He accepts Morty destroying his phone. Without the storm in his mind, he stops focusing on mad scientist concerns and focuses on morning hikes and manners. But it's hollow - he feels an obligation to family but not his typical personality disorder spikes of attachment and frustration towards them.

After his toxic self vows to toxify the planet in revenge, standing in the rubble of his home, he offers to pick some basil and prepare a meal. He chooses to try to be non-confrontational and avoidant in that moment. He had just proved himself capable of confrontation; Rick has battled himself plenty, both metaphorically and literally. And yet.

I believe they feel as if they had divorced themselves from those aspects of themselves embodied by the toxic, shadow selves. They knew how NOT to be based on their past experiences but didn't quite know what and how to be instead.

The presented solution was to recombine the two for instant return to equilibrium. But was it necessary?

I believe if the Toxic selves had stayed in the tank, the healthy ones would in time suffer more toxins in the form of new and reemerging neuroses, compulsions, and flaws. It would keep the detox center in business.

I'm not sure if the Toxic forms would be able to be rehabilitated. They are purified negative mood slime. The pair did have egotistic awareness and drives beyond the raw rage seen in the other slime creatures. There's an errant kernel of humanity there, just fueled by the worst parts. And therapy is boring work.

Furthermore, only Healthy Rick has a childhood form in regeneration, and he is birthed from the original body of Booger Rick, mind you.

Rather than merely embodying a false dichotomy of diametrically opposed archetypes, the healthy and toxic forms provide insight to existence without reflection, growth, and improvement strategies. Life as an American Psycho or a pleasant avoidant is no more desirable than engaging in the world as a vengeful madman or self loathing, fearful child. You can find moderation in embodying these aspects of the self.

The spa offered a shortcut to recovery. It was treated as the final destination instead of a stepping stone to better aid recovery and heading in a new direction. That's too much of a chore, and self-improvement would make for bad television. Still, lasting bliss and self acceptance is work. As ongoing and tedious as wiping your ass.

tldr - Fuck Tammy.