I compare my job to that of a fireman. Majority of my shifts (I prefer nights and weekends, I have a schedule with few weekday shifts) I have duties I need to do daily. There are two different main "jobs", and I alternate those nightly/daily with whoever I'm working with. Some nights my duties might mean I drive by something and look at a few levels, and I'm done in 15 minutes. On a 12 hour shift. Other nights I might have 2 hours of rounds/duties. Some nights I get called to do a job where I sit in a shack and push a few buttons over the course of an hour, but most of that time is waiting, so I make sure to have "portable hobbies".
I can't go home, because I'm there for the emergencies, and even though I live just a few minutes away, that would take too long to respond. I could add more work, but why? I used to be a gung-ho worker, but that got beat out of me a few years ago. So now, I read, watch tv/movies, mess around on the internet, sew, quilt, crochet, calculate my retirement, update my budget, etc. I plan to write out a bunch of recipes for my son on nights where I'm not motivated to do other stuff. The guys who have to run the show on those off shifts have told me they don't care at all what I do on my shift, as long as I do my rounds and answer my radio when they call me. The job is probably 95%+ stress-free, but when there is stress, it goes from 0 to 100 in instantaneously.
I do have some shifts where I'm "on" nearly the entire time, but those are few and far between. Even then, nothing is so important that I can't break away to use the restroom.
At this point in my life, this is pretty much my dream job (outside of being able to do something similar in a foreign country). For full benefits, I have to wait until I'm 57 to retire, but I can handle that with this job and schedule.