I work in IT and I don't need to think about that project that's running late or whatever. Yeah, I have to turn off my work laptop, but that's more akin to taking off my apron if I worked in a bakery.
Sure, it sometimes happens that I'm working on some interesting project, and I may find myself thinking about it after my workday is done. But it's because I generally love what I do. It wouldn't surprise me that, say, a pastry chef would possibly think about combining ingredients in some different way, too.
I think the only job where you absolutely wouldn't have to think about it is if you don't have any kind of agency and only do what you're told. I'm not sure that I would enjoy that kind of job.