When I quit at a bank, I wrote in my departure letter that I wished to have my 2 week's notice waived.
They denied my request and tried to convince me to stay for the two weeks, saying very sarcastically, "Oh, I guess you have a new job starting tomorrow."
That ticked me off to no end, so I said bluntly "No. There is another much more obvious reason why I wish to leave immediately," and spelled out in no hesitant terms how he made the environment toxic, and he just demonstrated by his response why I didn't want to be there.
I then pointed out that forcing someone to stay in a position they've already voiced they don't wish to be in creates a de facto disgruntled employee, which the corporate policy identifies as a direct security threat.
I told him I'd happily write that up if he wished me to provide it to his director, and then escorted myself out.
A month later, that manager got demoted and moved to another business unit. Apparently things really fell apart after I left, and people used my leaving as evidence of his outright lack of professional leadership.
I did have a new job starting the next day, but it wasn't his business to know.
Did I mention any of this in the interview? No, and not even after I got hired. I focused on the opportunity they had to offer, which was very aligned with my career goals. Better than sounding like I'd bad-talk them when I decide to move on from there. Likewise, I left nothing in writing that would burn bridges from the previous place.
But while it's probably not good to dwell too much on negative things in such situations in general, I would feel able to give an exec-level summary of why those workplaces seemed to be unhappy and ineffective compared to others. It helps that I've been on both sides of the hiring desk many times.
And don't lie - that gets you into a very bad place. I had one chap I helped hire be dismissed for having lied about a thing we might have been able to accommodate.
"My (current|previous) position was no longer a good fit for me" is not a lie and is about as tactful as you can be and I would leave it at that. When probed simply explain that the environment had changed and was no longer what it was when you started. It's okay to just say "it was time to move on". Anything probing beyond that I would be as professional as you can but tell the truth.
"Why are you leaving Soul Crusher & Associates?" As much as I've learned and grown as $currentRole, I've always hoped to be able to work as $interviewRole and can see myself contributing so much more at $newCorp because ...